Engine build question

[bryankichler]

I am currently working on plans to rebuild my engine. I am a deployed soldier and noticed right before i left my current engine had metal shavings in the oil so im going through it.

I am going for a cam change mainly current cam is unknown I have no means of checking prior owner said 292 duration pretty vague. I also had a problem with it running lean so carb choice would help. So to shorten this up below is what I currently have and current plans for the engine looking for criticism and Ideas.

Currently have
Engine: GM 355
Heads: 487x slight porting 2.02 int / 1.6 exh (1.6 roller rockers)
Compression: 10:1
Intake: Edelbrock EPS
Carb: Edelbrock 600cfm
Ignition: MSD HEI Distributor w/ stock coil

Projected Plan
Engine: The plan is to freshen up the bottom end bearings rings arp bolts throughout
Intake: Edelbrock Performer RPM Air-Gap
Carb: Holley 750 DP (open to suggestions)
Cam: Comp Cams Magnum 280 Hydraulic Roller (Adv Dur 280/280, Dur @ .50 224/224, lift .525/.525, lobe separation 110) (Open to suggestions)
Ignition: MSD HEI Distributor w/ Accell super coil and MSD 6AL

To help in giving advice below is the rest

Transmission: 700R4 from Pro-Built Automatics Street/Strip
Converter: Stall will be determined on cam requirements
Rear End: GM 12 Bolt w/ Eaton Posi 4.10 Gears and 28" tires

Driving Conditions: Street/Strip. It will see short trips cruise's, 3 blocks to work and back. The occasional long trip (driven to track, reason for overdrive cut down RPM's on the highway)

I am sure some of you guys can really pick this apart. While deployed I have the time to take advice and do this right. I am not looking for anything extremely radical just something to match up with what I already have. HP/TQ figures would be killer to.

[ll____b0t____ll]

Well as you have decent compression and semi good flowing heads Ide recomend a cam with 230*/230* duration at 50
Ide keep the lift under 500 so maybe 480 lift somewhere around there anything after 500 lift you start running into tapping heads and clearance issues with vales in some cases "not all".
Ide go hydrolic lifter just for easy life no problems
if you like a lumpy cam ide go for a 108-110 lobe seperation
Ide run a 2500-3000 stall
I had this combo in my last 350 and it was good for 409 HP and 416 TQ
But thats just a decent example of a puffed up street engine you could go more radical with some head work but youll start running
into vacuem loss and in my personal opinion anything needing over 3000 stall is very unfreindly on the street.

As far as carb im a holley person myself ide recomend a 750 double pumper I couldnt tell you what jetting as i dont know your elevation but a good start is 70 primaries and 72 secondaries.
If thats to lean up the jetting and check squiter nossle size.
I had a lean condition with a large carb like that too and chased it until i found steal in my oil it was a wiped lobe causing the lean condition not the carb.

heres a link to a good cam and if you get one from them youll see the quality serpasses CompCams in a big way , not to mention the steal filings you found may be from lifters and bad lobes from CompCams natorous failing lobes.

link for Shneider cams: http://schneidercams.com/288H_sbchyd.aspx

[Warrens69GMC]

What year 355?

[bryankichler]

This is what I was looking for good advice. I do like that cam pretty similar to the comp magnum 280 hydraulic flat tappet. I also emailed AED carbs for advice on carb selection they also pointed me toward a 650 holley. I agree on the metal shavings most likely being from the cam and lifters I have seen it more and more often lately thats why I am leaning more towards a roller setup plus to free up some more power.

[bryankichler]

Originally Posted by Warrens69GMC

What year 355?

Its been a while i dont recall the casting number off the top of my head. it is a 4 bolt main and if I remember right it was late 60's to early 70's block dont quote me on that.

[djracer]

That jetting would only work if the carb had power valves front and rear. A standard jet set on a 750 is 72s and 82s with a power valve only in the front. I personally would run a 650 dp on a good street motor.

[Bad70sbchevy]

I have about the same setup in my truck. I'm running a holley 600 dp on a 292 duration cam. I drive it every day too. I'm guessing its making around 425hp.

[stich626]

for a street truck a 750dp is to big get a 650 if more street than track a vac 2nd carb over the d/p , if you're gonna hot shoe it around town you might want to stay with a d/p
I've never had a comp cam fail if it was broken in correctly.
what size tires you gonna run the 700r4 3.08 first gear and 4:11's are gonna make first gear useless.. with a 26-28" tall tire
how are you coming up with 10 to 1 ?? or is that what you are shooting for?
if this is more of a hot toy for 80% street driving, you might want the vac 2nd carb to help with mpg , if thats not an issue then straight to the d/p but a 750 is to large if you where setting up this engine with a single plane intake and a cam to run the powerband up into 6500-7500rpm then yes go for a 750.. otherwise you're gonna have lazy throttle response..
your cam with .525 lift is listed with 1.5 rockers your lift with your 1.6 is going to more than likely hit thy pistons, even with the 1.5 rockers you'll have to check piston to valve clearance, and degree in the cam..
you don't say if your block is a roller block. but this is a retro fit roller cam for older blocks (non roller) the cam is self is 297.oo(comp site) now add the lifters,pushrods,springs
the kit #K12-430-8 cam/lifters/pushrods/springs/timing gears and chain/spring retainers and locks is 986.oo (comp site)
just an fyi on what you're getting yourself into..
you might be better off getting (or at least looking at) finding a g.m. roller block

[Marv D]

I really don't get why everyone is having issue with the roller cam and increasing lift to get some time above .3 on those old heads. He's going to have the engine apart,, cutting for valve clearance if need be is a whopping $50 or $60. The benefits of a roller lobe as far as efficiency will pay that $ back in no time with fuel prices like they are. And the benefit of a roller profile getting those old heads (or any hed) to a decent level will pay him back in grin factor the first time he stomps the right foot to the floor.

but lets talk a bit about those heads....

The 487x castings were the introduction of the 1972 demise of the muscle car power. So these are not some super-duper casting and barely on par with 186 or 461/x . Not bad, but the bigger 76cc chamber and the little 152cc intake runner is clue they were rearranged to bring compression and power down. A buddy kept a record of every casting that went across his Sunnen flow bench and would flow heads just for the heck of it when they were in his shop. The list has two 487 entires and one is 203cfm @ .600, the other is 206cfm. Compare that to a 461 that went 216,, or a bone stock vortec that is 239cfm. Also let's keep in mind that in 70, the pinnacle of the muscle-car wars,,, GM offered a 370HP 350 cu. in motor. 11:1 compression, mechanical flat tappet cam near .5 lift as they ever offered, 780cfm q-jet (as I recall) HOW there are so many 400+HP 355's out there with 9:1 compression and factory GM casting...... I won't go there ,, just say that I am amazed at how well some guys build motors in Desktop dyno (and that is NOT to point fingers at anyone,, just a general statement of the numbers you see all over the internet,,, ooops, sorry for that off-topic rant!!!)

Brian, with loosing a cam, you need to pull the motor apart and get the debris out, replace the bearings,, your plan is SOLID buddy.

Your thoughts of Roller cam,, I'm 1000% with you there. Choose wisely,, compliment the heads, compression, driving style and the rest of the package.

A RPM Airgap intake is minimum I'd use if your building a street strip motor. Like others I'd much rather see you with a good 750 vacuum secondary carb because of the street / driver duty being so much more than this build being a track star.

But the more serious and expensive part of my suggestion... evilbay those heads and buy something that will compliment the rest of the build. Your throwing some serious coin at this thing with that parts list, but crippling yourself with those 4 decade old heads. Even with some pocket porting / bowl cleanup you will be lucky to get much over 220cfm and an honest 1hp per inch. Today there is Soooo much available for small block heads that will blow the socks off the old GM castings. My advice is scrap up another $1500 for the budget and let's talk about a set of heads. The returns (in terms of grin factor) on that will be a heck of a lot more than a any other dollar I see listed in your parts list.

OK, I'll get out my asbestos shorts here and get ready to get flamed for spending your money while your off defending our way of life. So I'll say THANK YOU SIR FOR YOUR SERVICE before I get burned down LOL.

[stich626]

Originally Posted by Marv D

I really don't get why everyone is having issue with the roller cam and increasing lift to get some time above .3 on those old heads. He's going to have the engine apart,, cutting for valve clearance if need be is a whopping $50 or $60. The benefits of a roller lobe as far as efficiency will pay that $ back in no time with fuel prices like they are. And the benefit of a roller profile getting those old heads (or any hed) to a decent level will pay him back in grin factor the first time he stomps the right foot to the floor.

]

no issue with him wanting a roller, just that a retro fix kit is a grand, and it maybe cheaper to find a roller block as he is rebuilding anyways..
and not everyone knows that .545 lift will (most likely)need flycutting..
it was just an fyi.
some dream big with small budgets.. and it's better he find this out now than after buy'n up parts and being short on funds to finish it..

[bryankichler]

Originally Posted by stich626

for a street truck a 750dp is to big get a 650 if more street than track a vac 2nd carb over the d/p , if you're gonna hot shoe it around town you might want to stay with a d/p
I've never had a comp cam fail if it was broken in correctly.
what size tires you gonna run the 700r4 3.08 first gear and 4:11's are gonna make first gear useless.. with a 26-28" tall tire
how are you coming up with 10 to 1 ?? or is that what you are shooting for?
if this is more of a hot toy for 80% street driving, you might want the vac 2nd carb to help with mpg , if thats not an issue then straight to the d/p but a 750 is to large if you where setting up this engine with a single plane intake and a cam to run the powerband up into 6500-7500rpm then yes go for a 750.. otherwise you're gonna have lazy throttle response..
your cam with .525 lift is listed with 1.5 rockers your lift with your 1.6 is going to more than likely hit thy pistons, even with the 1.5 rockers you'll have to check piston to valve clearance, and degree in the cam..
you don't say if your block is a roller block. but this is a retro fit roller cam for older blocks (non roller) the cam is self is 297.oo(comp site) now add the lifters,pushrods,springs
the kit #K12-430-8 cam/lifters/pushrods/springs/timing gears and chain/spring retainers and locks is 986.oo (comp site)
just an fyi on what you're getting yourself into..
you might be better off getting (or at least looking at) finding a g.m. roller block

The 10:1 compression ratio is going off the build sheet this was a PO build I am assuming domed pistons since the chambers are 76cc. I was kinda wondering about the 1.6 roller rockers i have those available and checking clearance was in the plans. Now with the roller cam yes i am aware of the cost but like marv d mentioned it will be well worth it. The amount of cams ive seen go bad in my area over the past couple years the roller will help ease my mind plus the benefits of having a roller. Switching to a newer block may run as much if not more than just using a retrofit. The gearing issue thanks for bringing that up point me in the right direction right now it runs th350 turbo with 3.73's and 28" tires but the 700r4 is going in what would you recommend on gearing or tire diameter

Originally Posted by Marv D

I really don't get why everyone is having issue with the roller cam and increasing lift to get some time above .3 on those old heads. He's going to have the engine apart,, cutting for valve clearance if need be is a whopping $50 or $60. The benefits of a roller lobe as far as efficiency will pay that $ back in no time with fuel prices like they are. And the benefit of a roller profile getting those old heads (or any hed) to a decent level will pay him back in grin factor the first time he stomps the right foot to the floor.

but lets talk a bit about those heads....

The 487x castings were the introduction of the 1972 demise of the muscle car power. So these are not some super-duper casting and barely on par with 186 or 461/x . Not bad, but the bigger 76cc chamber and the little 152cc intake runner is clue they were rearranged to bring compression and power down. A buddy kept a record of every casting that went across his Sunnen flow bench and would flow heads just for the heck of it when they were in his shop. The list has two 487 entires and one is 203cfm @ .600, the other is 206cfm. Compare that to a 461 that went 216,, or a bone stock vortec that is 239cfm. Also let's keep in mind that in 70, the pinnacle of the muscle-car wars,,, GM offered a 370HP 350 cu. in motor. 11:1 compression, mechanical flat tappet cam near .5 lift as they ever offered, 780cfm q-jet (as I recall) HOW there are so many 400+HP 355's out there with 9:1 compression and factory GM casting...... I won't go there ,, just say that I am amazed at how well some guys build motors in Desktop dyno (and that is NOT to point fingers at anyone,, just a general statement of the numbers you see all over the internet,,, ooops, sorry for that off-topic rant!!!)

Brian, with loosing a cam, you need to pull the motor apart and get the debris out, replace the bearings,, your plan is SOLID buddy.

Your thoughts of Roller cam,, I'm 1000% with you there. Choose wisely,, compliment the heads, compression, driving style and the rest of the package.

A RPM Airgap intake is minimum I'd use if your building a street strip motor. Like others I'd much rather see you with a good 750 vacuum secondary carb because of the street / driver duty being so much more than this build being a track star.

But the more serious and expensive part of my suggestion... evilbay those heads and buy something that will compliment the rest of the build. Your throwing some serious coin at this thing with that parts list, but crippling yourself with those 4 decade old heads. Even with some pocket porting / bowl cleanup you will be lucky to get much over 220cfm and an honest 1hp per inch. Today there is Soooo much available for small block heads that will blow the socks off the old GM castings. My advice is scrap up another $1500 for the budget and let's talk about a set of heads. The returns (in terms of grin factor) on that will be a heck of a lot more than a any other dollar I see listed in your parts list.

OK, I'll get out my asbestos shorts here and get ready to get flamed for spending your money while your off defending our way of life. So I'll say THANK YOU SIR FOR YOUR SERVICE before I get burned down LOL.

Marv I dont have a lot of info on the heads the most ive seen and heard is they are good heads and it currently runs like a scalded ape. The info you supplied makes me want to push more towards a set of vortec's or something better. I know ive ran into a few circle track guys that would love to have my heads so that could potentially offset the cost right there. This is also all planned for a 66 C10. Thanks for the support I will be returning home within the next couple months and im going to have some personal time with my truck month vacation to start getting everything ready.

[stich626]

you're rebuilding a standard bore roller block core short block (block/crank/rods/pistons/)
are 100.oo
if you are rebuilding and that includes a overbore. you're gonna need new pistons.
so whatever's in your engine is moot.. only reason to stay with a non roller block is if your crank is a forged crank.. if it's cast.. a newer roller block with one peice rear main seal.. will save you coin.. again it all depends on what you end up doing, if it's a hone and rering rebuild ya it be cheaper to stick with what you got..
today I'd never build a flat tappet .. so I'm withya there..
it sounds like your just doing a hone and go rebuild,
remember when you ad arp rod bolts you need to resize the rods big end..
with that cam and 1.6 rockers the pistons are gonna be needing a fly cut, that marvie says is only 60 bucks and thats great , now add the cost of balancing the crank/rods/pistons with rings, that 60 bucks is now more like 3 bills plus..
after you find out what pistons are in the thing, you'll have a better idea on what you can run without needing to fly cut and rebalance the lower end, cause at that point, it's foolish not to rebuild the short block correctly..
just my take..
as far as gearing I'd leave the 373's with 28" and the 700r4
295/50/15's are only 26.7" tall and with some power you'll need some rubber on the road

[bryankichler]

your right on the hone rering on this one. I got this motor in a deal it was a fresh build my guess is improper break in on the cam or sat long enough for the everything to dry up oil system wasn't primed and drove I am guessing its the cam going and yes i agree. I do think i would run into clearance issues but i know it was 292 duration cam i dont recall all the other specs but most ive seen are not under .500 lift so im thinking there is already some worked. I am satisfied with the power it puts out now mainly looking to convert over to a roller cam and id like to get some a little more out of it you can never get enough.

on the roller block its hard to find a good deal on one plus they usually have vortec heads which are great but with higher lifts they will need work just to get them to handle everything.

I do agree once i get home and tear into it it will make things a lot easier. I do not plan to purchase anything till its tore down and been to the machine shop to have it all checked.

[Handfull 54]

Bryan,

Looks to me as if your plan is reasonable. I agree with some of the others that the carb is a little to big. You will be better served with a 650 cfm carb. This will give you a better throttle responce for all around street driving. Save some money and get some better heads. Edelbrock has some heads you could look at as well as some other companies. Don't go crazy with the heads either. Keep everything compatable, and you will do fine. Thanks for what your doing for all of us and be carefull out there.

[stich626]

Originally Posted by bryankichler

your right on the hone rering on this one. I got this motor in a deal it was a fresh build my guess is improper break in on the cam or sat long enough for the everything to dry up oil system wasn't primed and drove I am guessing its the cam going and yes i agree. I do think i would run into clearance issues but i know it was 292 duration cam i dont recall all the other specs but most ive seen are not under .500 lift so im thinking there is already some worked. I am satisfied with the power it puts out now mainly looking to convert over to a roller cam and id like to get some a little more out of it you can never get enough.

on the roller block its hard to find a good deal on one plus they usually have vortec heads which are great but with higher lifts they will need work just to get them to handle everything.

I do agree once i get home and tear into it it will make things a lot easier. I do not plan to purchase anything till its tore down and been to the machine shop to have it all checked.

if it's a comp 292 it's .501 lift.. you're looking at .525 with 1.5 rockers and you have or get deal on 1.6 rockers, whatever work you think the heads have, I'd check

[bryankichler]

I think ill go with the 650 carb. the cam is just up in the air i do know there is a good difference and likely to run into clearance issues that's why im entertaining ideas on the cam maybe something more compatible with my build maybe im throwing to much cam in heads may not flow good enough to support it. I am grateful for the info its great but im new to roller cams ive been told you can go higher lift with a roller and not have problems. now that's something ive been told i prefer an opinion from others that have more experience with rollers. i know hydraulic i probably wouldn't go more than .500 lift and for sure not with 1.6 roller rockers unless i planned for a lot more work to be done, working valvetrain geometry checking clearance issues the works.

[Marv D]

Originally Posted by stich626

...... the pistons are gonna be needing a fly cut, that marvie says is only 60 bucks and thats great , now add the cost of balancing the crank/rods/pistons with rings, that 60 bucks is now more like 3 bills plus.....

Is that some feeble attempt at sarcasm because you didn't like what I said sonny boy,,, you better go back to your HotRod and Carcraft magazines and learn how to balance a motor.

You only use 1/2 of the reciprocating weight in figuring the bob weight for balancing. Cutting a .1" deeper pocket in an existing valve relief of a 400 or 500+ gram piston is going to cut MAYBE 1.5-2 grams. To put it in simple terms... ONE gram of steel such as the big end of the rod is about equal to the volume of a 1/4-20 nut. Aluminum,, being roughly 1/3 the weight of steel,, well you do the math.

NOT TO MENTION that there is more weight difference between a standard 4.00" piston and a 4.030" piston this motor was rebuilt with then any flycut! Do you honestly think the PO / builder rebalanced over the difference between a standard and 4.030 piston,, or let me ask,, do you KNOW what that difference is,,, how about 8-12 grams IF you are using identical material and manufacturer. Use some of the KB / Badger crap and it's more like 35+ grams different than stock dished piston this crank was more than likely throwing around originally. But you think a 2g. cut on a piston is a big deal on a street motor and needs rebalancing......... interesting!

[stich626]

Originally Posted by Marv D

Is that some feeble attempt at sarcasm because you didn't like what I said sonny boy,,, you better go back to your HotRod and Carcraft magazines and learn how to balance a motor.

You only use 1/2 of the reciprocating weight in figuring the bob weight for balancing. Cutting a .1" deeper pocket in an existing valve relief of a 400 or 500+ gram piston is going to cut MAYBE 1.5-2 grams. To put it in simple terms... ONE gram of steel such as the big end of the rod is about equal to the volume of a 1/4-20 nut. Aluminum,, being roughly 1/3 the weight of steel,, well you do the math.

NOT TO MENTION that there is more weight difference between a standard 4.00" piston and a 4.030" piston this motor was rebuilt with then any flycut! Do you honestly think the PO / builder rebalanced over the difference between a standard and 4.030 piston,, or let me ask,, do you KNOW what that difference is,,, how about 8-12 grams IF you are using identical material and manufacturer. Use some of the KB / Badger crap and it's more like 35+ grams different than stock dished piston this crank was more than likely throwing around originally. But you think a 2g. cut on a piston is a big deal on a street motor and needs rebalancing......... interesting!

yaya it still has to be balanced, and I don't need car craft to tell me that,
I've run no balance set ups they don't last long,
"Is that some feeble attempt at sarcasm because you didn't like what I said sonny boy" nope, just stating facts, the flycuts maybe only 60 bucks(not around here,but anyways) then you have to balance it, and yes I'd expect that rebuilt engine with non stock pistons to have been balanced when built..
the o/p said he thinks they are dome pistons and a 550+ lift will need more than a light cut, no matter as nor you or I know what in it. and yes when I spin my 355 to 7800+ or my 358 to 9800 it better be balanced, BOY(TO USE YOUR WORDING
i'M OUT.
GOOD LUCK WITH IT, and thanks for serving