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Building an 11 second 70's nostalgic SBC

General engine tech -- Drag Racing to Circle Track

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treyrags
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Re: Building an 11 second 70's nostalgic SBC

Post by treyrags »

vortecpro wrote: Mon Apr 26, 2021 8:07 am
treyrags wrote: Mon Apr 26, 2021 6:35 am
vortecpro wrote: Sun Apr 25, 2021 8:12 pm Houston regularly sees a 30.3 baro and NEGATIVE 500-1000 below sea level. The NHRA altitude correction factor is .9405 for Denver, I've never raced in under 8000 DA Denver.
Houston is the exception, not the norm in Texas. The DA was 1800 yesterday less than 2 hours away from Houston.
I understand that, but Houston in the right time of the year is extremely fast. As the video I posted back a few comments depicts taking a mild production BBC street car that ran the best of 136 MPH in Colorado, within 5 passes in Houston in a 615 DA 30.0 baro constantly playing with the traction control with zero tuning went to 147 MPH-you have no idea whats its like racing in Denvers 23.70 baro. BTW I now moving/live in Horse Shoe Bay.

https://youtu.be/E1Wz5qZDPAk
Yes Houston can be as fast as anywhere, depending on how wet the air is. My Dad and I raced in Comp for 25 years in Houston. We also traveled and raced in West Texas, Colorado, New Mexico and other altitude regions. It is all relative. You can't get too excited about good numbers in mine shaft conditions or too down about slow numbers in low oxygen areas. Just be as prepared and tune the best you can.
jeff swisher
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Re: Building an 11 second 70's nostalgic SBC

Post by jeff swisher »

My 57 4 Door Chevy 210 is a daily driver, old school build.
Heavy also at 3600lbs and I have a trailer hitch on it that pulls my 20 foot pontoon.

Simple easy and cheap build.
350 2 bolt main with cast flat tops Stock rods and bolts.
601 heads with 1.84-1.50 valves as delivered from GM .
I ported the heads. Get the Book How to Build and Modify SBC cylinder heads.
Build and port your own heads.
Just about any old iron SBC head after porting will flow the same or darn close..Differences are in the chambers.

I run a simple 280H cam 230@ .050 .480" lift with stock GM 1.5 rockers and stock pushrods RPM intake and 750 carb 1407 Edelbrock.
They are simple and they work.

It ran 12.80's and my timing had retarded on me during the burnout to 28 total and killed the top end.
8.0 in the 1/8 mile Yea I had 4.56 rear gear.

So standard bore 350 2 bolt easy to find 601 heads with some porting and stock small valves, 230@ .050 cam 3600 lbs 12.80's on 91 octane.
I built a Nova for a friend and 3300 lbs with 601 heads 292H cam it went 115 MPH and 11.94 ET
1.94-1.50 valves.
Yep 4.56 rear gear..
His et would have been better but he wanted to shift at 7400-7500 every time it was a 357" cast piston flat top.
Another daily driver on pump fuel 91 octane from 7-11.
That was at Noble OK Thunder valley raceway.

I used to run old double humps but I actually like the 601 head better. I can unshroud the chambers the way i wish and still keep the chamber in the 57-62cc area without milling.

When I ran 186 double humps I milled them .060" to get the chambers smaller. Lots of porting on them.
Get that book.
https://www.abebooks.com/Build-Modify-C ... gKZMvD_BwE

You do a 383 stroker and you will have way more on the table and reach your goals easy.
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Re: Building an 11 second 70's nostalgic SBC

Post by VMC »

Man, people sure have become spoiled with all the mail order speed parts available these days, makes one wonder how anyone went fast at all back in the day. :roll:

Your goals aren't difficult to reach, but it will depend somewhat on what you're willing to tolerate on the street (camshaft manners specifically).

FWIW, a WELL TUNED `70 LT1 Camaro with headers, a working suspension, decent tires and a 4.10-4.56 gear had little difficulties going well into the 12's--and that's with a "lowly" vacuum secondary carb, a dual plane intake and heads that probably didn't crack 220 cfm. Now port those heads, cut the plenum divider down or go to a good period intake like a Holley Strip Dominator, add an appropriate camshaft and valve train and you're looking at an 11 second combination that'll be about as fussy as a hammer.

It ain't rocket surgery, and it's been done more times than can be counted.
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Re: Building an 11 second 70's nostalgic SBC

Post by canuc »

I like the 350 I recommend on page 2 over a 383 , easier to hook up on the street tires and higher rpm with same heads as 383 . Small tire stock wheels with a 4.88 gear . The alum case t10 will thank you . Get a scatter shield and a good flywheel and clutch setup . And try too keep the stupid grin off your face when you drive it . Don't think he's building a daily driver , if you can get it to idle below 1200 with a good carb you don't have a big enough cam and or heads .
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Re: Building an 11 second 70's nostalgic SBC

Post by ClassicRob »

canuc wrote: Mon Apr 26, 2021 10:15 pm I like the 350 I recommend on page 2 over a 383 , easier to hook up on the street tires and higher rpm with same heads as 383 . Small tire stock wheels with a 4.88 gear . The alum case t10 will thank you . Get a scatter shield and a good flywheel and clutch setup . And try too keep the stupid grin off your face when you drive it . Don't think he's building a daily driver , if you can get it to idle below 1200 with a good carb you don't have a big enough cam and or heads .
I agree. Its starting to look like a 355-383 with those TFS heads, old school manifold and a roller cam. I just figured there was some advise out there the old timers could come up with that would get me in the solid 12's using some old school stuff.
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Re: Building an 11 second 70's nostalgic SBC

Post by VMC »

355 short block with suitable internals for 7000 rpm
Z28 oil pan & baffle or equivalent aftermarket
186, 492, 370 or 041 heads ported, 2.02/1.60 valves
Crane 110981 flat tappet cam (252°/260° @ .050", 288°/296° adv., 106° LSA, .536/.554 lift)
Z28 intake with plenum divider removed or Holley Strip Dominator intake
780 VS or 750 double pumper carb
1 3/4" X 3" headers
GOOD clutch (adjustable if you're so inclined)
4.10 or 4.56 gears
28X10.5" tire
Appropriate chassis work

Doesn't get much easier--or cheaper than that.
canuc
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Re: Building an 11 second 70's nostalgic SBC

Post by canuc »

I agree VMC , build it with everything that was available in 77 right down to the lakewood trac bars and shocks not rocket surgery at all . The older head cores are about the only thing getting hard to get . I'd like a single pattern with 108 lsa with Z hi rise and full exhaust , isky z60 is what I was thinking or z35 with less gear than 4.88 . Or get a custom ground , wouldn't be bad money spent just don't think its a make or break deal . And I was joking about the 1200 idle , z60 should idle fine at 950 with 11-1 and a good 750 .
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Re: Building an 11 second 70's nostalgic SBC

Post by tblentrprz »

OP, if you're keeping 3.73 gears, then you need to be looking at tq production if your really interested in 1/4 mile goals (vs a hp # at high rpm). If auto and 26" tire you'll only be around 5800 in 1/4 based on 115mph (~410tq needed). if 28", 5400 (440tq). With pump gas and keeping with old school parts, not sure what you're expecting to produce for tq/ci ratio. Conservative puts you in the realm with a 383. If you change gear or it's a 4 speed, then more rpm and smaller cubes is more doable. Just for reference, a basic 383 9.5:1 will produce 440ftlbs @ 4500 and 430hp at 5400. If you do some basic head work and spec a cam to match, you'll exceed your goal. Aluminum heads, bump comp up to 11:1. I realize this isn't a recommended parts list, but a perspective to help meet your goals. Curious what others thoughts are moving a 3800lb rig with 3.73 gears.
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Re: Building an 11 second 70's nostalgic SBC

Post by F-BIRD'88 »

This is the point I am making. Even with a 383 the power is upstairs.. Needs RPM and mechanical leverage (gears) to move the mass quickly. You have to put the power to use.
383 (4.88) 355 (5.13) based on 27" sticky street/strip tires and 4 speed trans. Yes 115 ish MPH 7000 +/- trap RPM.
This is not that hard if physics/mechanics is emoyed. Same as was done on these cars in the 70's.. The heavier the car is the more mechanical leverage needed.
Everybody used Lakewood traction bars but the Cal-Trac type traction bars (which are also period correct) work BETTER. I'd use 'em.

The more weight you remove from the car the BETTER the result.. Especially if off the front end.
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Re: Building an 11 second 70's nostalgic SBC

Post by KnightEngines »

3.9-4.11 gears, 4500 stall, 383 cubes, 450hp will run easy 11's & be perfectly streetable.
Done it more times than I can count, I'm not guessing.
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Re: Building an 11 second 70's nostalgic SBC

Post by steve cowan »

KnightEngines wrote: Wed Apr 28, 2021 1:58 am 3.9-4.11 gears, 4500 stall, 383 cubes, 450hp will run easy 11's & be perfectly streetable.
Done it more times than I can count, I'm not guessing.
Yes-
My last years 383 combo
Dart 178cc cast iron head
SFT 235- 242 @ 0.050" 106-106LSA 0.500" lift
10.6 compression
Turbo 400- 5600 stall
4.11 rear gear 255/60/15 et radial
3650 pounds
11.71 @114
Moroso slide rule says 440hp max.
Simple combo,heaps of street miles ran consistent 11.7s all day.
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Re: Building an 11 second 70's nostalgic SBC

Post by F-BIRD'88 »

Thats peachy... This car is 3600+ driver 3800#
Its a 4 speed not auto
Moroso slide rule really says 114 mph 3650# needs 418 net horsepower (rear wheel)

This car is #3800 w/driver. To run 114 mph it will need 435 net hp.. Thats assuming it is geared at or close to correct.
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Re: Building an 11 second 70's nostalgic SBC

Post by steve cowan »

F-BIRD'88 wrote: Wed Apr 28, 2021 4:35 am Thats peachy... This car is 3600+ driver 3800#
Its a 4 speed not auto
Moroso slide rule really says 114 mph 3650# needs 418 net horsepower (rear wheel)

This car is #3800 w/driver. To run 114 mph it will need 435 net hp.. Thats assuming it is geared at or close to correct.
All things being equal-
Would like to think it would be faster with 4 speed,might not be quicker though factoring startline,traction,first gear ratio etc.
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Re: Building an 11 second 70's nostalgic SBC

Post by Rick! »

Quarter Pro estimates the following:
3600lbs, 3.73 rear gear, 455hp @ 6500, 2.85 1st gear: 11.97@112.5 with perfect traction and some clutch slip
3800lbs, 4.56 rear gear, 455hp @ 6500, 285 first gear: 11.99@111.8 with perfect traction and some clutch slip

The car is listed at 3662 lbs so the driver must be pretty light for the above to happen.
The little 10 bolt is not going to be happy very long and the wave spring posi will give up even earlier.

Car needs the bumpers swiss cheesed and the foam supports lightened up a bunch, a glass hood and aluminum heads should make it near 3600 with a driver. Lose the AC system for at least another 50lbs and add another 50hp, easy peasy.
Keep the Qjet, Holleys are heavy.
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Re: Building an 11 second 70's nostalgic SBC

Post by ClassicRob »

If y’all want to settle this, find me some 292’s! I’ve got the money. I’m looking daily, sometimes 2-3 times.

The car is a 4 speed. No option car. It might be lighter than 3600, that was a guess. But if is 3600, it’d be 3820 with me in it. I’m broad shouldered.

3.73’s are staying. It’s gotta go down a 60mph highway.

I also thought Cal Traks were a late 80’s thing??
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