And so it begins................

[highperf4x4]

Originally Posted by JohnC

This has become a very informative thread. I don't know squat about all these different numbers, and such.

That's the reason for discussions like this. Education. Other than that, I would keep my secrets to me self.

Originally Posted by scotts62

As for the gears heck yeah but if your planning on hopping up the engine that much and want something to last just plan on spending about $500 on an Auburn Locker, you will like that bad boy

I'm going to talk to you some more about this.

Originally Posted by scotts62

No tbi is work truck material i would stick some vortec heads on it just mildly pocket port them, have them stud and guide plated put a 292 comp cam in it for 500/501 lift, do the 383 short block and find some mud puddles

But thats just me..

I have a fresh bored and decked block and stroker crank thats ground and ready to go just waiting for the 62

Your vortecs have already had some spring work then? Factory vortecs are only good for .470 lift because the retainer hits the seal plates under the valve springs that the factory modified to stop all oil from getting past the valveguides to meet stricter emission requirements.

[scotts62]

Originally Posted by highperf4x4

That's the reason for discussions like this. Education. Other than that, I would keep my secrets to me self.

Your vortecs have already had some spring work then? Factory vortecs are only good for .470 lift because the retainer hits the seal plates under the valve springs that the factory modified to stop all oil from getting past the valve guides to meet stricter emission requirements.

Yeah i hear ya on the secrets, i worked at a automotive machine shop for almost 3 yrs now i dont know everything but know some tricks

Thats all i did was bore blocks, valve jobs, drill for guides, machine for bigger springs, machine heads for studs and guide plates. You would cry if you knew what i paid for mu new engine over haul

I dont have any vortec heads, The TBI's i just did are just built plano jano. I have a set of double hump cheater heads that have the accessory holes for alternator brackets that im going to bore for 2.02 1.60 valves, they are already machined for studs and guide plates so it will be a quick upgrade for the most part.

[highperf4x4]

Originally Posted by JohnC

I thought you liked the big block in the 72?

I must have lost ya. The 355 is going into the '72 to give me more time to build the 402 the way I want it. Then it will go back in.

Originally Posted by scotts62

Not to ruff the feathers at all but to get the HP out of the rockers you will need the roller cam to go with it and decreed in to actually notice any good out of the $250+ rockers, i had the full roller 1.6 rockers on the 62 with the tunnel ram and the only thing that really seemed like it changed was the thump of the cam since it makes a tit more lift. Now i didnt want to spend the dyno money every time i changed something just to see what helped or not so i cant say that it helped or hurt..

As for the gears heck yeah but if your planning on hopping up the engine that much and want something to last just plan on spending about $500 on an Auburn Locker, you will like that bad boy

I don't run roller rockers. I run "roller tip" rockers. There isn't any need to degree a cam to switch from stock 1.5 to 1.6 ratio rockers. It only increases valve lift. The duration/overlap will remain the same. The addition of approximately 50hp is a combination of going from a 76cc combustion chamber to a 65cc combustion chamber, a larger intake runner, and increased valve lift without having to change the cam. The 355 already has roller tip rockers but they're stock ratio. You can run roller tip rockers on any engine. They reduce drag on the valve train with the roller tips and they're alot thicker were the pushrod meets the rocker than a stock style stamped steel rocker so you won't shove a pushrod through like I did on the stock ones.

Here's a link to the rockers from summit for 80.00
http://www.summitracing.com/parts/CCA-1412-8/

I'll show you a pic of mine.






Now about this Auburn Locker.............. you gonna get me a better discount?

Originally Posted by '72customdeluxe

I don't forsee tbi heads getting anywhere near 400. They're horrendous. You might be able to get away with 10:1 with a larger than stock cam and a nice cooling system/cold air for the engine to breathe with the improved chamber design. 11:1, yeah. With a 30/30 cam

I might have to bring you up to speed on this.

I can build an engine with 305 heads and make more than 400hp. They just wouldn't hold up for long because they are light duty. TBI heads are not.

This motor isn't stock though. It's a 350hp engine right now! It's bored .030 over, forged flat top pistons, double roller chain, edelbrock 2102 cam, comp magnum roller tip rockers, balanced, blueprinted, etc. The heads are the original 1976 heads though. They have 76cc combustion chambers (milled to approx 72cc), 1.94 intake valves, 1.50 exhaust valves, screw in rocker studs, and single Z28 valve springs good for up to .520 lift. The TBI heads have the same size valves but with a smaller 65cc combustion chamber. They also have slightly larger intake runners for better flow. They also have a raised valve cover seat to reduce oil leaks around valve cover gaskets as high rpm from a performance engine always creates more blowby. They are certainly improvements over gen1 cylinder heads and have no disadvantages other than they are not as good as a vortec head which has an even larger intake runner. They WILL make more power on this engine than the heads on it now and they're a heavy casting.

I don't follow what you're trying to say on the compression though. The engine is 10:1 right now with the old heads. With the TBI heads (going from a 72cc combustion chamber to a 65cc combustion chamber) it will be 11:1. The issue will be fuel, not cam. There isn't enough octance even in super unleaded to keep an engine with 11:1 compression from burning a hole in a valve or a piston regardless of what cam you're running.

['72customdeluxe]

According to "PaulD" on thirdgen.org the 193 (350 1.94) heads flow this
INTAKE

Stock SP #193 . Modded SP modded Vortec

.100 70.7 68.1 55.8

.150 101.7 100 89.2

.200 124 125 123.5

.250 140 144 160

.300 146.5 154.7 186

.350 150.1 164.8 203.8

.400 154.7 171.3 228

.450 158.2 175.4 235

.500 160.4 177.4 228


EXHAUST

.100 47.8 51.7 42.9

.150 70.4 73.1 66.6

.200 85.1 93.7 90.1

.250 97.6 112.3 112.2

.300 112.3 129.7 129

.350 120.5 145 142.6

.400 125 156.3 152.6

.450 129.2 164.6 160.9

.500 129.2 162.5 166.5

The following parameters apply:

1. None of the heads had a three angle seat cut.
2. The L31 and stock 193 head used a single angle cut on the valve.
3. The modded 193 head used a 30 degree back cut on both the intake and exhaust valve.

What's it all mean? First of all, I make no claim to be a professional porter or even a good one, only what an educated amateur can do. It has been a knock against the 906 Vortec head that it does not flow as well as the later 062 casting. Looks like that might be right. I plan on relooking at the 906 exhausts to see what else may be able to be done.
The SP heads flowed very well at low lifts. The intake ports have a convoluted path with the pushrod on one side of the port, then the head bolt hole on the opposite side and severe undercuts below the bowl that were too deep to remove even opening the bowl diameter to 1.75. From .200 and up, the Vortecs flowed better.

Other observations are yours to make.

My apologies for not being able to format the data more clearly. It typed out clearly but I can't seem to get enough space between the columns.

['72customdeluxe]

Basically, don't waste your time. Your average 441/882 smogger will flow around 202 cfm stock. This will be a pile of dog mess if the numbers above are correct

[highperf4x4]

I can make out the list no problem. I don't know PaulD though. Are these his own numbers? Actually the 461 casting with 64cc chambers and 2.02 intake valves can flow up to 224cfm. With 441 you're looking at 76cc chambers. So, flow is not the only consideration unless you're blown or supercharged.

My question would be this. At what lift do the old heads pull the 202cfm and does he have a comparison chart for those heads by lift?

I am still dropping from a 72cc chamber to a 65cc chamber and increasing valve lift by way of rocker ratio although I can do that to either head.

['72customdeluxe]

Originally Posted by highperf4x4

I can make out the list no problem. I don't know PaulD though. Are these his own numbers? Actually the 461 casting with 64cc chambers and 2.02 intake valves can flow up to 224cfm. With 441 you're looking at 76cc chambers. So, flow is not the only consideration unless you're blown or supercharged.

My question would be this. At what lift do the old heads pull the 202cfm and does he have a comparison chart for those heads by lift?

I am still dropping from a 72cc chamber to a 65cc chamber and increasing valve lift by way of rocker ratio although I can do that to either head.

The thing about the list spacing are his words, I know 461's will flow better than a smogger. I just mentioned that even a crap smog head is better. 40 cfm is no where near made up by the compression, just running a .04 quench height along with two eyebrow flat tops will get you over 9:1 with 76cc heads. The flow numbers on the 882's are from my chevy high performance small block build book. here they are.
I e
.050 39 34
.100 70 59
.200 125 109
.300 175 136
.400 204 143
.500 205 144
.600 206 145
The miniscule low lift flow advantage the tbi heads have over a smogger wouldn't win still. Also, by the time you get the tbi heads ready you could get reman vortecs for around 280 or so a pair on ebay

[highperf4x4]

As for the valves and seats, all of my heads have 3 angle valve jobs. I won't run heads without this mod and I won't install heads without a valve job unless they're pre-assembled performance heads.

[highperf4x4]

What is he considering a modded SP? Is he referring to porting? Where does he list the valve size and seat angles? A 3 angle valve job improves flow rate. What I'd like to see is a side by side comparison of the TBI's and the "smoggers" with the same size valves, ported, and the 3 angle valve grind. That would be very helpful.

As for the ebay vortecs can you grab me a link for those? You would usually pay that much for EACH head especially if they already had the 3 angle grind. Shipping has to be considered too.

I can have the TBI's ready for much less than 280.00.

I appreciate the conversation by the way. In 20 years of building performance engines the one thing I've learned is that I haven't learned it all. I'd also like to add that for a 16yr old you've been doing some studying and my hats off to you for that and I will think over what you've presented here. Stay involved hombre!

['72customdeluxe]

Originally Posted by highperf4x4

What is he considering a modded SP? Is he referring to porting? Where does he list the valve size and seat angles? A 3 angle valve job improves flow rate. What I'd like to see is a side by side comparison of the TBI's and the "smoggers" with the same size valves, ported, and the 3 angle valve grind. That would be very helpful.

As for the ebay vortecs can you grab me a link for those? You would usually pay that much for EACH head especially if they already had the 3 angle grind. Shipping has to be considered too.

I can have the TBI's ready for much less than 280.00.

I appreciate the conversation by the way. In 20 years of building performance engines the one thing I've learned is that I haven't learned it all. I'd also like to add that for a 16yr old you've been doing some studying and my hats off to you for that and I will think over what you've presented here. Stay involved hombre!

I'll get you a link to that guy's thread about the tbi heads, but the ebay vortec were simple stock everything remans, i've seen them from 280-300 somthing. However a three angle valve job isn't going to make up for the 70 cfm (160->23x.xx) deficit from the tbi heads to the vortecs I wouldn't think. I was going to pick up some tbi heads cheap because those motors make decent power stock, but then I saw the flow numbers. Another option is patriot vortec heads. They're cheap for new performance heads but still expensive 600$. I won't list all the specs but here's a link https://www.patriot-performance.com/...&cat=76&page=1

[highperf4x4]

Ok, before I hit the sack I'm gonna drop some final info on ya just for the sake of improving general knowledge.

TBI heads are considered low flow heads because they have "high swirl" intake runners provided by a "ramp" in the runner itself. They're not alot of good above 4000rpm. However, the high swirl runners make really good low end torque and improved "fuel economy". The 193 casting of the TBI head also has the 65cc combustion chambers making them pretty much the only ones worth my time. Especially since my truck is a '72 with a TH400 as the tall 1st gear needs all the low end torque and compression it can get with no stall converter and since it isn't an overdrive the additional fuel economy will be nice too.

As with most modifications you have to think application specific. I'm working out a performancne build for my 4x4, not this '72. This is just a temp engine swap that will put close to 400hp in my '72 for the time being. I could cetainly dump more money into the 355 and make lots of power but that would defeat the purpose of the temp engine. It's only going in the truck to give me time to build the 402bb that's in it now. I don't want to spend money on it. The TBI heads will make an improvement over my old heads for the '72 and I got them for free! The 383 I'm buidling for the 4x4, as stated before, will be a completely different setup with Vortec heads.

The discussion has been great though and feel free to provide any more info you dig up.

[JohnC]

This has become a very informative thread. I don't know squat about all these different numbers, and such.

[0331grunt]

No doubt!

[highperf4x4]

Yeah I've seen the patriot heads online. I'm a little skeptical about a company that can sell aluminum cylinder heads as cheap as they do. I'm not sure where they're cutting corners as I've never seen one of their heads up close.

Remember, the advantage of a TBI head is different than what people perceive. It's high compression and makes really good low end power for trucks and the high swirl runners make fuel burn alot more efficient for better economy. They're not a drag racing head though that's for sure. Fortunately GM was able to continue the "swirl" effect in the vortecs they simply changed the design and increased the size of the runners so it doesn't impede flow at high rpm.

['72customdeluxe]

Yep, they'll make torque for sure but the point I was argueing is that they'll make nowhere close to 400 horsepower

[highperf4x4]

Ok, I smell a challenge. Looks like I'll need a dyno sheet. If I win, you'll have to come up here and rub my feet!!



Alright, back to business. I picked up the goodies from the montster today and I've run all the numbers just for kicks.

Block (I'll need new main caps) - 10243880
350...95-00...4bolt...Vortec truck, Gen.I crate motors and "ZZ4", roller cam, one piece rear seal

Heads - 10239906
96-up...350.........."Vortec 5700", "L31", 64cc chamber, 170cc intake port, 1.94"/1.5" valves

Crank - 3951529B
400.......cast....large journal....3.75" stroke

The crank is stamped 383 and 10/10 without visible wear so it has plenty of life left in it. But, it's an older 2 piece rear seal and it's cast so I'll probably just go with a forged crank. He also included the rods which look good too but they're also stock (and someone has mixed the caps up) and I'd like to use H-beam. Of course, then I'd want to punch the valves out to 2.02. Oh man, it's never enough!!!!!

[jgh64pkup]

why would you need new main caps?
they make an adapter for the one piece block to drop in a two piece crank
http://www.gmpartsdirect.com/perform...CATID=883.html

[scotts62]

I bought one of those adapters one time to use a crank that i had laying around hell it was over a hundred bucks and i could have exchanged a crank for 75 oh well i take the long road sometimes just for different scenery

[jgh64pkup]

good god i didnt know it was that high
you cant get a 383 crank for 75 bucks can you?

[highperf4x4]

Originally Posted by scotts62

Yeah i hear ya on the secrets, i worked at a automotive machine shop for almost 3 yrs now i dont know everything but know some tricks

Thats all i did was bore blocks, valve jobs, drill for guides, machine for bigger springs, machine heads for studs and guide plates. You would cry if you knew what i paid for mu new engine over haul

I dont have any vortec heads, The TBI's i just did are just built plano jano. I have a set of double hump cheater heads that have the accessory holes for alternator brackets that im going to bore for 2.02 1.60 valves, they are already machined for studs and guide plates so it will be a quick upgrade for the most part.

Boring for some 2.02 valves huh? You and I need to get together for some coffee soon brother. I've got things to talk about!

Originally Posted by jgh64pkup

why would you need new main caps?
they make an adapter for the one piece block to drop in a two piece crank
http://www.gmpartsdirect.com/perform...CATID=883.html

Because some of the caps were missing young grasshopper. See you made assumptions!

Originally Posted by jgh64pkup

good god i didnt know it was that high
you cant get a 383 crank for 75 bucks can you?

No but he was likely talking about 350 cranks and his connections.

[scotts62]

Originally Posted by jgh64pkup

good god i didnt know it was that high
you cant get a 383 crank for 75 bucks can you?

No but to grind a 400 crank to fit in a 350 is around $150 which still isnt too bad.

Originally Posted by highperf4x4

Boring for some 2.02 valves huh? You and I need to get together for some coffee soon brother. I've got things to talk about!

[JohnC]

Glad to hear you got the stuff man. The ole red beast is really going to scream now!

[highperf4x4]

Originally Posted by scotts62

No but to grind a 400 crank to fit in a 350 is around $150 which still isnt too bad.

Fortunately this crank is stamped "383" right beside the 10/10 so it's been done already

Originally Posted by JohnC

Glad to hear you got the stuff man. The ole red beast is really going to scream now!

yes................ yes it is.

[jgh64pkup]

i didnt make assumptions
damn thats gonna cost you for those main caps
line boring and honing isnt cheap
i looked into it because i wanted splayed caps (i dont anymore!!!!)
it would probably be cheaper to get another block

[highperf4x4]

Yes you did, you assumed I was referring to the rear seal issue young grasshopper.

I usually align bore anyway. Don't you? And straighten the crank?

I don't hone anything though. I bore the cylinders if that's what you meant.