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Gen 1 SBC 5.7L vs 1994 truck TBI SBC

 
Loren Young
I love my Chevy Chevette!
Posts: 13
Joined: 03/14
Posted: 03/22/14 02:55 PM

I have a 1966 Chevelle Malibu that has a 72 Nova 350 in it that I have been building. Recently my 1994 GMC sierra took a dump and I was wondering if I should replace my Gen 1 SBC with the truck TBI SBC in my Chevelle? Which motor is better for performance upgrages and general performance. I just put a new Air Gap RPM intake and Holly 650 cfm electric choke vacuum secondary carb on Gen 1 SBC. Are there parts that I can take from TBI motor to put on Gen 1 or the other way around? Which heads are better, both are OEM? Thanks  

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shyrgfuh3
V-6 Camaros rule!
Posts: 67
Joined: 01/14
Posted: 03/22/14 03:02 PM

do you have a 94 350 ci gmc truck eng with a carburetor that has throttle body injection?

is it a chev or gmc eng?

you want to put the blown up truck eng in your chevelle?

what dsoes this have to do with a 72 nova?

can you please explain again just EXACTLY in detail what in the world it is you want to do and why.  

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Loren Young
I love my Chevy Chevette!
Posts: 13
Joined: 03/14
Posted: 03/22/14 03:21 PM

lol sorry if confusing. Ok the car is a 66 chevelle and it is the one I want to build the best engine for. Even though it is a 66 chevelle it currently has a 72 Nova engine in it. My 94 GMC Sierra engine is good but the tranny went out. I want to know if the 94 GMC TBI engine is a better engine for my chevelle than the 72 Nova engine that is in it now. Are the internals of the GMC engine, ie crank, camshaft, lifters, rockers, heads better than 72 Nova engine? Should I do a complete swap? Should I steal parts from GMC engine for Nova engine? If I swap the blocks can I put my RPM air gap intake on GMC engine or will it not fit due to heads being different? Is my holly carb better than TBI system? Just trying to figure out my best options based on what I currently have. Thank You for any help you can provide.  

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shyrgfuh3
V-6 Camaros rule!
Posts: 67
Joined: 01/14
Posted: 03/22/14 03:29 PM

THE 72 BLOCK IS GOOD.

DO YOU WANT A MILD, MEDIUM OR HIGH PERF ENGINE?

WHAT HEADS EWXACTLY ARE ON THE 72 ENG NOW?  

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Loren Young
I love my Chevy Chevette!
Posts: 13
Joined: 03/14
Posted: 03/22/14 03:30 PM

The car I want to use is my 66 Chevelle and I want my best option for it based on what I have available. The car currently has a Gen 1 72 Nova motor in it that has the RPM Air Gap Intake and Holley Carb. My 94 GMC trucks tranny went out but the motor is still good. Is the TBI motor from the GMC a better option for my chevelle than the Gen 1 that is in it? Should I keep Gen 1 in it and steal parts from GMC motor? Should I take block from GMC and put it in but put parts from GEN 1 motor on it? Is my carb better than the TBI system? Will my intake not match up with GMC heads? Are the internals of the GMC better, ie crank, camshaft, lifters, rockers and heads? What is my best option for building a performance engine based on what I have? My preference would be an LS or LQ9 engine but that is not in the budget. Thank you for any advice.  

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shyrgfuh3
V-6 Camaros rule!
Posts: 67
Joined: 01/14
Posted: 03/22/14 03:34 PM

i know nothing about the gmc eng. are the heads aluminum.

what kind of perf do you want ie., drag car freeway dlier or inbetween.

you nova and gmc heads are likely junk for a perf build. can you afford new heafds?

nered the casting numbers off your nova heads.  

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Loren Young
I love my Chevy Chevette!
Posts: 13
Joined: 03/14
Posted: 03/22/14 03:37 PM

Medium I believe, the car will not be on the track but I will drive it frequently just not as daily driver. The current heads have 333882 stamped in them. I think they are the original heads to the block.  

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shyrgfuh3
V-6 Camaros rule!
Posts: 67
Joined: 01/14
Posted: 03/22/14 03:41 PM

did you see this post?

i'll check on the heads now.


i know nothing about the gmc eng. are the heads aluminum.

what kind of perf do you want ie., drag car freeway dlier or inbetween.

you nova and gmc heads are likely junk for a perf build. can you afford new heafds?

nered the casting numbers off your nova heads.  

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Loren Young
I love my Chevy Chevette!
Posts: 13
Joined: 03/14
Posted: 03/22/14 03:44 PM

GMC engine should be same as chevy engine. The sierra and Silverado are the same truck. No money for new heads, maybe in the future but for what good heads cost I could buy a used LQ9 6.0L engine off of Craigs List.  

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shyrgfuh3
V-6 Camaros rule!
Posts: 67
Joined: 01/14
Posted: 03/22/14 03:49 PM

ok, you can not use the nova heads for any type of perf build. they have 76 cc chambers so your compression is way too low.

i will look into the 94 heads. is this the lower wider block?  

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Loren Young
I love my Chevy Chevette!
Posts: 13
Joined: 03/14
Posted: 03/22/14 03:57 PM

I don't know which block it is, I can look into it but will be a while. Thanks for the help.  

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shyrgfuh3
V-6 Camaros rule!
Posts: 67
Joined: 01/14
Posted: 03/22/14 04:10 PM

ok your heads are cast number 10110810. they have 1.94 and 1.5 valves just like your nova heads nowever the ports look bigger and the chamber size is 64 cc which is much better. i would use these heads. there are no special parts in the 94 eng.

you need around 3.31 - 3.43 gears for a moderate performance car.

cam around a comp cams xe268h or similar lunati and new springs.

hyper or forged flat top pistons.

scorpion full roller rockers.

arp screw in rocker studs

i would use the old carb intake from the nova if it will fit.

650 - 700 cfm annular boost venturi carb.

balance the engine.

buy an ati crank damper.

arp rod bolts  

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Loren Young
I love my Chevy Chevette!
Posts: 13
Joined: 03/14
Posted: 03/22/14 04:16 PM

The casting number on the GMC heads is 14102193  

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Loren Young
I love my Chevy Chevette!
Posts: 13
Joined: 03/14
Posted: 03/22/14 04:28 PM

I found this article which helps a lot

Hot Rod TBI Heads

Thank you for all the advice. I greatly appreciate it and will post what I decide to do.  

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shyrgfuh3
V-6 Camaros rule!
Posts: 67
Joined: 01/14
Posted: 03/22/14 04:29 PM

ok i'll check it out.

are they aluminum?  

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