SBC to BBC swap question.... (Isearched first)

[nikwho]

Hey guys,

I'm mid swap with my '68. Putting my 433" BBC in as soon I make a final cam choice. It's an all forged rotating assembly, 4.280" x 3.76" BBC that's getting a solid roller cam and the FiTech MeanStreet 800 EFI kit.

My question pertains to engine frame brackets. I was going to order the POL tubular towers, but didn't like the thought of moving my engine up and forward. I'd sooner go down and back, even if it meant notching the firewall. Anywho, I've heard of guys using the SBC towers. I'm not opposed to welding my own engine mounts up, but would prefer a bolt in affair.

My truck is a '68 GMC C20, with the high hump floor. Its got an '86 C10 suspension crossmember. I've got Heddman BBC Camaro headers. I've heard about guys using the sbc towers, with mixed feedback. Seems like the consensus is that it'll fly, sometimes, If you use headers. The end all test will be to stick the engine in the truck. My plans are to run an HEI distributor, Camaro BBC full length headers, Victor Jr. Manifold w/ FiTech throttle body. I am planning on using head studs, but may be better off with bolts, so that the engine doesn't have to come out to remove a head.

My question is, have any of you done a BBC swap with the SBC frame mounts? Adversely, have any of you tried to do the swap this way and we're not able to finish the swap because of clearance issues? I want my engine as low and far back as I can make it. So, sight inconveniences are worth while to me to keep the engine as low and far back as plausible. As in, I don't mind pulling the engine out to remove heads and/or change distributors. It's not about saving the $130 that the POL tubular mounts cost. I just don't want to unnecessarily move the enine further up or forward than it must be.

Thanks for your guys' time!
NIK C

[Ruffin]

I'm doing the bigblock swap also and I like this setup...Going for $231 on ebay...you get engine and trans mounts

[nikwho]

Yeah, I almost bought the POL tubular towers this morning. Almost finished typing in my card number and had second thoughts. I just don't want to move the engine forward and up if I don't have to. I'm glad I didnt, because I almost bought the wrong ones, too. I saw and almost purchased these 68-72 towers, but later realized that my '68 frame isn't the "late 68-72" narrow frame. I think that IF if go the POL tubular route, I'd need the earlier '63-'67 mounts, since my frame doesn't step in like the frames pictured. My frame rails stay wider through the area of the engine frame mounts.

But, like I stated, I'm hopeful to hear about someone getting away with the SBC frame mounts, but one post that my search pulled up suggested that I couldn't work, but that seemed like an incompatibility between bbc & sbc mounts.

I'm trying to figure out if anyone has pulled off their BBC swap with the SBC frame mounts.

Another question. Does anyone know how far up and forward the POL tubular mounts move the engine? I was hopeful that I could get away with keeping the transmission in its current location, without creating a need to shorten or lengthen the driveline. Doesn't seem that difficult to keep the transmission put.

[nikwho]

Originally Posted by Ruffin

I'm doing the bigblock swap also and I like this setup...Going for $231 on ebay...you get engine and trans mounts

FWIW, if you buy that kit direct from POL, it's $221 right now.

[randy500]

Read this one...
http://67-72chevytrucks.com/vboard/s...d.php?t=122645

[nikwho]

I'm also stumped as to which set of POL engine mount brackets to buy, as they indicate the one set works on '63 to early '67 trucks and the other works on late '68 to '72 trucks. Well, what's a guy supposed to do if he has a late '67 to early '68 truck? I waneed to get in on their April Fools Day sale that ends tonight, but accoring to their descriotions, neither will work in my '68 GMC that does NOT have the narrow frame, as their photo illustrates. My frame stays wide.

Perhaps I need to just bolt my BBC up to my transmission where I want it and weld up some engine stands, like I had to on my '59 Apache. Cheaper that way anyway. I'm just getting to a point where I really like bolt in parts that show up in the mail powder coated and ready to bolt in. Saves a lot of time. Guess I'm getting a little lazy! But, now I can't figure out which set of towers I'm supposed to buy and I am not going to cut my frame rails.

[nikwho]

Originally Posted by randy500

Read this one...
http://67-72chevytrucks.com/vboard/s...d.php?t=122645

Ahh, I had found this one in the past but didn't see it with today's search. I'll read now and hopefully find all of the answers! Thank you!

[randy500]

And this one, last post BB with POL mounts

[nikwho]

That is indeed the thread that I was hopeful to find and read again. That sounds pretty definitive that the SBC brakes won't work. BUT, now, after reading about the small sbc bolt holes and the big BBC mount holes, I feel like my frame mounts had the bigger holes. I wonder if when the SBC was installed into the truck by a PO, if it was installed into the aforementioned BBC frame mounts, that have the bigger holes! I may be getting incredibly luckily here & may have the BBC stands installed already! I'll figure out tomorrow what mounts I have. Thank you for the link to TX FF's thread!

[nikwho]

I swear, I'd just buy the POL brackets right now if I knew which ones fit my frame. Back to searching the interwebs.

[James the III]

You got bigger problems..
a solid roller cam, and a tbi efi.. Might want to rethink this.

[Spullar]

Originally Posted by James the III

You got bigger problems..
a solid roller cam, and a tbi efi.. Might want to rethink this.

Please expand on this. Enquiring minds would like to know.

[James the III]

Originally Posted by Spullar

Please expand on this. Enquiring minds would like to know.

Welp.. if you've moved to a solid roller, you've moved past the limits of a hyd roller.. So you now have a cam with tons of reversion ,overlap and then you top it with a tbi??
good luck.. The fuel distribution problems should be "epic"

[nikwho]

Hmm, I'm in need of an education on this.

Here's the Comp cam I've got on order:
https://m.summitracing.com/parts/cca-k11-771-8

Here's the FiTech MeanStreet EFI kit that I've also ordered:
https://m.summitracing.com/parts/fif-30008

I wasn't aware of an issue or incompatibility, but I'd love to learn more! Also, perhaps this is a nomenclature issue. FiTech refers to their injection system as a throttle body. I assumed (perhaps foolishly) that TBI = Throttle Body Injection. And Solid roller = Mechanicol roller cam. With that said, this will be my first non-hydraulic roller cam engine as well as my first non carburetor engine (in an older car), so I'm definately venturing into unknown territory. My short block is built, but I'm not married to this cam yet.

[weq92f]

I too am shopping cams for BBC. From the looks of that cam spec, you are building a mid-to-upper RPM HP and torque maker/screamer. The cam RPM range is 2500 to 6000, calls for 10:1 minimum compression and 2800 stall.

Is that your intention? Just curious as I've been thinking the BBC in my case is much better suited to low-to-mid RPM torque/power ( think 5200 MAX RPM ).

Regarding the TBI. Just make sure your intended HP range of your motor doesn't exceed the expected MAX HP of your TBI unit, which is probably around 600 HP. You can purchase TBI units with higher HP rating ( bigger or more injectors ).

-klb

[James the III]

Tbi is good for mild engines.. TBI that cost a ton that self learn and allow you to still go in and adjust everything to fine tune, dial it in even better ,do better.. at that point, you might as well. put on real efi.. not a glorified carb with injectors in it.
mpefi is your best bet for a mild to wild high rpm engine..
There is no gain to a solid roller other than rpm.. and even more aggressive lobe ramps..
The bad is solid rollers need to be check, often . And don't like low rpm use , idle to 3500 rpm.. from lack of oil. the newer lifters have addressed this, but are not cheap and still need to be checked often and sent back to be rebuilt often.. Sure solids sound cool, but if you are not ready for the upkeep.. you are in for a headache..

If it's a mild solid roller (street roller) get a hyd roller.. you won't be giving up much other than higher rpm

[davepl]

Another option for TBI is run to run two of them (like dual quads), though that's not likely required until 500-600hp or so, depending on the original source of the TBI (if we're talking GM TBI). If it's aftermarket TBI you're likely fine for capacity.

I'm not going to debate it with James, as I'm neither super passionate nor knowledgeable about it, but I don't see a huge advantage in MPFI, even though that's what I've always done. It's great for emissions, but doesn't make more power than TBI. I don't know that it necessarily deals with intake reversion better than TBI, though it might for some reason I haven't thought it. Even MPFI has a throttle body, so where the injection happens... does it matter for the purposes of having a big cam? I can't think of why.

I'm just guessing, but he might just be saying your cam is too much for the street, and that's almost always true:

People that don't have a cam yet want a bigger one.
People that already have it want a smaller one.

Pick the cam you want to LIVE with, not the one you want to TELL people about.

[James the III]

Originally Posted by davepl

Another option for TBI is run to run two of them (like dual quads), though that's not likely required until 500-600hp or so, depending on the original source of the TBI (if we're talking GM TBI). If it's aftermarket TBI you're likely fine for capacity.

I'm not going to debate it with James, as I'm neither super passionate nor knowledgeable about it, but I don't see a huge advantage in MPFI, even though that's what I've always done. It's great for emissions, but doesn't make more power than TBI. I don't know that it necessarily deals with intake reversion better than TBI, though it might for some reason I haven't thought it. Even MPFI has a throttle body, so where the injection happens... does it matter for the purposes of having a big cam? I can't think of why.

I'm just guessing, but he might just be saying your cam is too much for the street, and that's almost always true:

People that don't have a cam yet want a bigger one.
People that already have it want a smaller one.

Pick the cam you want to LIVE with, not the one you want to TELL people about.

The problem is reversion in the intake.. and the TBI systems are designed around more mundane engines.. not a solid roller high strung one...
So the software for it. might not have enough adjustment to deal with it..
The tbi the injector is at the carb flange the mpefi it's at the valve..
There is a reason the holley tbi hp system is 2200-2500 and the sniper is 999.00
the later will puke on a high strung engine.. even if it comes under the rated hp level of the unit..
Carbs on engines like this took pro's to tune..
The basic low to mid level tbi win't have enough features in the tuning to control the fuel reversion and some cyl being rich and others being lean..
sequential mpefi is the best bet on engines like this..
I agree many got to the bottom of the page to pick a cam..

[Ruffin]

Originally Posted by nikwho

FWIW, if you buy that kit direct from POL, it's $221 right now.

Is the $221 shipping and taxes?

[nikwho]

Originally Posted by weq92f

I too am shopping cams for BBC. From the looks of that cam spec, you are building a mid-to-upper RPM HP and torque maker/screamer. The cam RPM range is 2500 to 6000, calls for 10:1 minimum compression and 2800 stall.

Is that your intention? Just curious as I've been thinking the BBC in my case is much better suited to low-to-mid RPM torque/power ( think 5200 MAX RPM ).

Regarding the TBI. Just make sure your intended HP range of your motor doesn't exceed the expected MAX HP of TBI unit, which is probably around 600 HP. You can purchase TBI units with higher HP rating ( bigger or more injectors ).

-klb

Yes sir. That was the plan. To build a high revving big block, hence the 3.76" stroke. Was looking at the aforementioned cam and the FiTech MeanStreet 800HP rated EFI kit, on a Victor Jr. intake. Was looking at trying to make around 600 HP. Figured that cam would pull well i to the 6,500-7,000 RPM range. Would be at about 10.76:1 static, IIRC. I dont have all of my chicken scratch notes near by and we looked at so many cams that numbers are starting to blend together. The truck will be a manual transmission, though currently an auto and converter should stall around 2,800-3,000 and my new Currie fabricated 9" has 4.11:1 gears and should hold up. This truck won't be seeing the strip. Will be a weekend warrior/hot rod that'll see a few autocross events per year. After the engine swap, I'll begin my 3 link design/build and I'll start seriously looking to find a transmission, so after the 3 link is done I can get my drive line figured out. I thought that was a pretty solid cam choice that would work pretty well for my intended purposes, from the research that I've done and the conversations I've had with folks that know a lot more than myself. But, like I said before, I'm not married to it. I do know that I want to be able to wind this 433" engine up pretty high. If I was gonna put a low RPM cam that built lots of low RPM torque in it, I'd run a 4", or more likely, a 4.25" stroke crank.

Ruffin, I doubt it. I was just on POL's site last night ordering my tubular frame stand and that was the price listed for their April Fools sale, I believe they called it. I believe that I got the tubular frame stands for $116, though I want to say that they added a solid $20-25 for shipping, etc.

[James the III]

R u willing to pull the intake and lifters out every 1000-1500 miles?
and check them? and have the truck down every time those 1000.00-1800.00 lifters need to be sent back to be rebuilt?
Have you asked the efi maker and others how it does on an engine that doesn't get on the cam till 3500-4000 rpm and how the self tuning software does with the reversion in the intake, and the o2 signal because of it.?
I haven't seen any bbc build correctly with longer strokes 454/468/489/496/540/etc not spin to 7500 .. The old wives tail of a long stroke can't spin is well..
You have the valvetrain and light valves to go to 7500rpm ?
nevermind the correct sized heads..
you're using main studs right..

[randy500]

That cam is a little cammy but should work for your intended purpose with manual transmission and your gears.

I run this one K11-771-8, 230/236 duration I think. I run a 4spd, 10.5 or so compression and 3:07 gears in a Corvette and its great, had some Idle issues with the stock quadrajet but worked that out. Premium fuel only.

Your fuel injection, are you able to change the fuel curve, spark and idle air with that one? I haven't kept up with all of them. If yes then keep it, otherwise try to find something you can tune yourself, its not that hard to learn basic tuning, I think all of the programming is Excel based, learn excel and experiment!

If the cam or FI doesn't work like you want ,you obviously have a shop to change it out to something that works for you better. Cam change is relatively low dollar, FI, not so much so make sure you like the one you buy and it will work now and for future upgrades.

[Mike C]

The Comp Mechanical roller in my Camaro has been there since 1988. The oil pressure fed lifters will live fine on the street. My setup probably has 25,000 miles or so? Not driven a lot, but has been reliable.

And $1000 for mechanical roller lifters?! Hardly. $400 a set. But check out the mechanical vs. hydraulic roller dyno test on engine masters on YouTube. The small power gain probably not worth the extra hassle on a street driven truck.

I just finished putting together my 434 big block short block. (427/390 hp from a '69 Corvette) and went with the smallest nitrous hydraulic roller Comp makes. I plan on doing my damndest to run the 'vette manifolds and want the added exhaust duration of the nitrous grind to make up for the reduced exhaust flow. My goal lower than yours at 350 whp, but the hydraulic vs. mechanical discussion is same.

I bought the 68-71 frame stands and mounts, the CPP big block power steering setup and 67-68 375hp 396 Camaro deep groove pulleys. I'm planning on large cap HEI and the 70-72 LT-1 air cleaner. But if the large diameter closed element filter won't clear I will run a ready to run small cap electronic setup. I have the MSD in my Jimmy but would consider the Jeg's.

[randy500]

Originally Posted by Mike C

The Comp Mechanical roller in my Camaro has been there since 1988. The oil pressure fed lifters will live fine on the street. My setup probably has 25,000 miles or so? Not driven a lot, but has been reliable.

And $1000 for mechanical roller lifters?! Hardly. $400 a set. But check out the mechanical vs. hydraulic roller dyno test on engine masters on YouTube. The small power gain probably not worth the extra hassle on a street driven truck.

I just finished putting together my 434 big block short block. (427/390 hp from a '69 Corvette) and went with the smallest nitrous hydraulic roller Comp makes. I plan on doing my damndest to run the 'vette manifolds and want the added exhaust duration of the nitrous grind to make up for the reduced exhaust flow. My goal lower than yours at 350 whp, but the hydraulic vs. mechanical discussion is same.

I bought the 68-71 frame stands and mounts, the CPP big block power steering setup and 67-68 375hp 396 Camaro deep groove pulleys. I'm planning on large cap HEI and the 70-72 LT-1 air cleaner. But if the large diameter closed element filter won't clear I will run a ready to run small cap electronic setup. I have the MSD in my Jimmy but would consider the Jeg's.

Mike were doing a similar build...
I'm dressing out my crew cab engine just like a '69 big block vette engine too.
I didn't buy the deep groove pulleys yet but do have the 69-71 frame stands, open element GM air cleaner, chrome GM valve covers. I'm using small cap MSD distributor because I don't like the look of the HEI and the MSD looks stock and blends in better. I will also be running the shielded corvette spark plug wires to complete the look.

I haven't installed it yet and hope the vette exhaust manifolds work...I will post up when I do a test fit.

Where did you source the deep groove pulleys?

[James the III]

Originally Posted by Mike C

The Comp Mechanical roller in my Camaro has been there since 1988. The oil pressure fed lifters will live fine on the street. My setup probably has 25,000 miles or so? Not driven a lot, but has been reliable.

And $1000 for mechanical roller lifters?! Hardly. $400 a set. But check out the mechanical vs. hydraulic roller dyno test on engine masters on YouTube. The small power gain probably not worth the extra hassle on a street driven truck.

I just finished putting together my 434 big block short block. (427/390 hp from a '69 Corvette) and went with the smallest nitrous hydraulic roller Comp makes. I plan on doing my damndest to run the 'vette manifolds and want the added exhaust duration of the nitrous grind to make up for the reduced exhaust flow. My goal lower than yours at 350 whp, but the hydraulic vs. mechanical discussion is same.

I bought the 68-71 frame stands and mounts, the CPP big block power steering setup and 67-68 375hp 396 Camaro deep groove pulleys. I'm planning on large cap HEI and the 70-72 LT-1 air cleaner. But if the large diameter closed element filter won't clear I will run a ready to run small cap electronic setup. I have the MSD in my Jimmy but would consider the Jeg's.

What are the specs of this baby solid roller.. As that is what it is..
No reason for a solid until you pass what a hyd can do.. and what they could do in '88 and now are not the same..
For a solid roller that is past the point that a hyd roller can function , you are not running 400.00 a set lifters..