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Building an 11 second 70's nostalgic SBC

General engine tech -- Drag Racing to Circle Track

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ClassicRob
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Building an 11 second 70's nostalgic SBC

Post by ClassicRob »

I am building an engine for my 77 Z28. Most of us can agree the good old days were in fact good and missing those days has inspired me to build a period correct engine for my weekend toy. This car sees mostly the car shows, very limited track use but DOES see some stoplight to stoplight action here and there. My goals are simple, mid 11's - low 12's, drives great on the street and looks like its from the era.

There have been some great advancements in the SBC arena, which would normally make this build easy. AFR heads, roller cam, and decent carb with longtubes and voila!

But I dont want to do that. I want a FT cammed, old school headed, old school carb, period correct 70's street machine. The car is a 3600lb 77 Z28 with a 4 speed, power brakes and no a/c.

What are my best options?
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Re: Building an 11 second 70's nostalgic SBC

Post by novadude »

I'm gonna say a basic 70 LT1 (11:1, 2.02 heads, etc) with some modifications will get you close. Probably gonna need to plan on revving it... hotter solid lifter cam, headers, lots of gear, etc. I would think that would put you low 12s....
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Re: Building an 11 second 70's nostalgic SBC

Post by ClassicRob »

novadude wrote: Thu Apr 22, 2021 4:01 pm I'm gonna say a basic 70 LT1 (11:1, 2.02 heads, etc) with some modifications will get you close. Probably gonna need to plan on revving it... hotter solid lifter cam, headers, lots of gear, etc. I would think that would put you low 12s....
Im going to use the stock 2 bolt block probably, and just add some splayed caps to it. Its a 010 block which I think should suffice. I need specifics, head numbers (old camel humps 461's?) - are there any other choices out there?
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Re: Building an 11 second 70's nostalgic SBC

Post by bobmc »

stroker crank
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Re: Building an 11 second 70's nostalgic SBC

Post by F-BIRD'88 »

That "3600 lb " car will weight 3800 lbs with you in it.
Which is it low 12's? or mid 11's ? Big difference in engine horsepower required @ 3800 lbs all in street trim to get there.
The fast 70's era cars were stripped down weight to bare bones race ready weight 3200 lbs max. (under 3400 lbs w/driver)
Big 4.56++++ gears.
Any of the ERA factory heads will need extensive full porting to get there . Big difference between a 68-72 Nova and a pig tank weight 77 Camaro.

Better to use modern stuff diguised to appear era correct.
3800 lbs will need 450 hp for low 12's 550 hp for mid 11's ET slips..
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Re: Building an 11 second 70's nostalgic SBC

Post by ClassicRob »

F-BIRD'88 wrote: Thu Apr 22, 2021 5:09 pm That "3600 lb " car will weight 3800 lbs with you in it.
Which is it low 12's? or mid 11's ? Big difference in engine horsepower required @ 3800 lbs all in street trim to get there.
The fast 70's era cars were stripped down weight to bare bones race ready weight 3200 lbs max. (under 3400 lbs w/driver)
Big 4.56++++ gears.
Any of the ERA factory heads will need extensive full porting to get there . Big difference between a 68-72 Nova and a pig tank weight 77 Camaro.

Better to use modern stuff diguised to appear era correct.
3800 lbs will need 450 hp for low 12's 550 hp for mid 11's ET slips..
Again, this information is NOT WHAT I AM ASKING FOR!! I need specific well known part numbers for SBC performance stuff of the vintage era!

I know what HP level it takes to run what number... Ive been there. I am asking for details. Thanks.
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Re: Building an 11 second 70's nostalgic SBC

Post by BLSTIC »

There have also been significant advances in tuning, particularly carb turbo stuff, if forced induction is a consideration.

Nobody really knew much about how to use them properly and tune for them back then, but applying modern knowledge to old school parts should get you better results than most people did back then. You could definitely have a streetable engine with a moderate amount of power from early turbo tech if you do the carb tuning, manifolds, head modifications, and cam selection using modern knowledge. Heaps of lag and a high boost threshold for the power, but that's half the fun of keeping it old school.

The only modern parts I'd compromise on are electronic ignition and a boost retard unit, but you can get/make two way vacuum advance cans if you're dedicated to using minimum electronics.
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Re: Building an 11 second 70's nostalgic SBC

Post by KnightEngines »

Do you want it externally period correct or period correct right through?
I'd go 383 cube with scat pro I beam rods & modern pistons with 1mm/1mm/2.8mm ring pack.
292 heads if you can find them & ported by someone who knows them well.
Strip dominator intake 300-25.
Old style 850 pumper holley - but send it to someone to have screw in air bleeds etc fitted.
Cam something like 264/270 on 108 centres, 1.6 ratio rockers.
11:1 comp.
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Re: Building an 11 second 70's nostalgic SBC

Post by Kenny M »

KnightEngines wrote: Thu Apr 22, 2021 7:22 pm Do you want it externally period correct or period correct right through?
I'd go 383 cube with scat pro I beam rods & modern pistons with 1mm/1mm/2.8mm ring pack.
292 heads if you can find them & ported by someone who knows them well.
Strip dominator intake 300-25.
Old style 850 pumper holley - but send it to someone to have screw in air bleeds etc fitted.
Cam something like 264/270 on 108 centres, 1.6 ratio rockers.
11:1 comp.
I built something very close to this combo. Ported 186 GM 202 heads 262 266 on a 106 11 to 1 Mahle pistons 4781 Holley 300-25 Intake
The engine Dynoed at 565HP and 500FTLBS.. It ran 10.70 in a 3400LB Nova with a T400 and 456 Gears with small 9" slicks.
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Re: Building an 11 second 70's nostalgic SBC

Post by DeezNutz »

Do yourself a favor and ditch the flat tappets... so much of a PITA these days. Too much risk of crappy cam cores and lifters. Put a roller hydraulic or solid in it and don't look back.

I won't ever do another performance engine on a flat tappet.
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Re: Building an 11 second 70's nostalgic SBC

Post by vortecpro »

This is very easily done. 355, ported fuelie production heads, 2.02/1.60 valves, a redline solid lifter cam, 245/252/.550/108, Mahe two valve relief flattop pistons, product rods with ARP bolts, nice pan with oil control, Performer RPM intake, 750 Holley. My 445 HP all production solid lifter 327 in my 1/2 ton truck 1979 long bed will probably run high 11s in the right conditions, does run 12.70 @ high altitude.
Racing a NA NHRA stocker should be mandatory before any posting.
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Re: Building an 11 second 70's nostalgic SBC

Post by ClassicRob »

KnightEngines wrote: Thu Apr 22, 2021 7:22 pm Do you want it externally period correct or period correct right through?
I'd go 383 cube with scat pro I beam rods & modern pistons with 1mm/1mm/2.8mm ring pack.
292 heads if you can find them & ported by someone who knows them well.
Strip dominator intake 300-25.
Old style 850 pumper holley - but send it to someone to have screw in air bleeds etc fitted.
Cam something like 264/270 on 108 centres, 1.6 ratio rockers.
11:1 comp.
This is where I was headed on my own. 300-25 intake if I cam find one but I hadn’t looked for 292 heads. I thought about doing an externally looking only deal and running the TFS double hump heads with a roller... I still might. The flat tappet deal is still what I want to do, it’s just cooler for something like this.

Do you think that cam can be better? What you’re describing doesn’t sound too far off from an old school GM grind I know about.
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Re: Building an 11 second 70's nostalgic SBC

Post by ProPower engines »

ClassicRob wrote: Thu Apr 22, 2021 5:52 pm
F-BIRD'88 wrote: Thu Apr 22, 2021 5:09 pm That "3600 lb " car will weight 3800 lbs with you in it.
Which is it low 12's? or mid 11's ? Big difference in engine horsepower required @ 3800 lbs all in street trim to get there.
The fast 70's era cars were stripped down weight to bare bones race ready weight 3200 lbs max. (under 3400 lbs w/driver)
Big 4.56++++ gears.
Any of the ERA factory heads will need extensive full porting to get there . Big difference between a 68-72 Nova and a pig tank weight 77 Camaro.

Better to use modern stuff diguised to appear era correct.
3800 lbs will need 450 hp for low 12's 550 hp for mid 11's ET slips..
Again, this information is NOT WHAT I AM ASKING FOR!! I need specific well known part numbers for SBC performance stuff of the vintage era!

I know what HP level it takes to run what number... Ive been there. I am asking for details. Thanks.
Well then you can just read any hot rod magazine from the 70's through the early 90's and get that info your self complete with dyno numbers.

What the guys are asking is valid questions and assuming you have a unlimited funds budget to do this one of the main issues is how are you going to mount accessories on a later model camaro with no bolt holes in the heads.
the readily available heads in iron from Dart will be much cheaper then playing with 50 year old obsolete heads that are impossible to locate to start with.
Crank and rod combos from back then were welded stroker stuff or billet custom.

I can go on but if you are really dreaming of a factory race car build using stock parts thats your call but the info you are seeking is generally vague at best as there is only a couple heads that fit the bill and they crack when ported which is why the suggestions of other options.

Maybe we should start by establishing how big your budget is for the engine alone for parts R+D as well as machining and assembly most of all how many inches of displacement do you want to start out with 283 327 350 400 etc etc etc???
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Re: Building an 11 second 70's nostalgic SBC

Post by KnightEngines »

ClassicRob wrote: Thu Apr 22, 2021 8:46 pm
KnightEngines wrote: Thu Apr 22, 2021 7:22 pm Do you want it externally period correct or period correct right through?
I'd go 383 cube with scat pro I beam rods & modern pistons with 1mm/1mm/2.8mm ring pack.
292 heads if you can find them & ported by someone who knows them well.
Strip dominator intake 300-25.
Old style 850 pumper holley - but send it to someone to have screw in air bleeds etc fitted.
Cam something like 264/270 on 108 centres, 1.6 ratio rockers.
11:1 comp.
This is where I was headed on my own. 300-25 intake if I cam find one but I hadn’t looked for 292 heads. I thought about doing an externally looking only deal and running the TFS double hump heads with a roller... I still might. The flat tappet deal is still what I want to do, it’s just cooler for something like this.

Do you think that cam can be better? What you’re describing doesn’t sound too far off from an old school GM grind I know about.
461/462 heads would also work, but the 292 is the pick of the bunch.
Cam specs I just pulled out my ass, I'd flow the heads & spec the cam from there.
A Solid flat tappet cam is more than capable of getting it done & you get the old school cranky idle to go with it.
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Re: Building an 11 second 70's nostalgic SBC

Post by ClassicRob »

ProPower engines wrote: Thu Apr 22, 2021 8:48 pm
ClassicRob wrote: Thu Apr 22, 2021 5:52 pm
F-BIRD'88 wrote: Thu Apr 22, 2021 5:09 pm That "3600 lb " car will weight 3800 lbs with you in it.
Which is it low 12's? or mid 11's ? Big difference in engine horsepower required @ 3800 lbs all in street trim to get there.
The fast 70's era cars were stripped down weight to bare bones race ready weight 3200 lbs max. (under 3400 lbs w/driver)
Big 4.56++++ gears.
Any of the ERA factory heads will need extensive full porting to get there . Big difference between a 68-72 Nova and a pig tank weight 77 Camaro.

Better to use modern stuff diguised to appear era correct.
3800 lbs will need 450 hp for low 12's 550 hp for mid 11's ET slips..
Again, this information is NOT WHAT I AM ASKING FOR!! I need specific well known part numbers for SBC performance stuff of the vintage era!

I know what HP level it takes to run what number... Ive been there. I am asking for details. Thanks.
Well then you can just read any hot rod magazine from the 70's through the early 90's and get that info your self complete with dyno numbers.

What the guys are asking is valid questions and assuming you have a unlimited funds budget to do this one of the main issues is how are you going to mount accessories on a later model camaro with no bolt holes in the heads.
the readily available heads in iron from Dart will be much cheaper then playing with 50 year old obsolete heads that are impossible to locate to start with.
Crank and rod combos from back then were welded stroker stuff or billet custom.

I can go on but if you are really dreaming of a factory race car build using stock parts thats your call but the info you are seeking is generally vague at best as there is only a couple heads that fit the bill and they crack when ported which is why the suggestions of other options.

Maybe we should start by establishing how big your budget is for the engine alone for parts R+D as well as machining and assembly most of all how many inches of displacement do you want to start out with 283 327 350 400 etc etc etc???
Factory race car build? 425hp shouldn’t be “dreaming”. This is just a nostalgia deal. Missing bolt holes isn’t a deal breaker. My budget is 12-14k.

I had 461’s on a 69 GMC step side that I got brackets for that held the alt and P/S. I think you’re right on the parts being harder to find.
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