olds 307 build
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olds 307 build
307 .040 offset ground crank 3.500 sj scat 6" rods 330 heads 54cc 1.875 intake 1.562 ex cam is solid 523" 530" 239 242 @50 106 lsa a holley street dominator and 650 carb ign is hei its goin in an 87 cutlass with a th 350 and 3500 10" appr 3400# 4.56 gears hopin for 12 sec et's i know just build 350 i'd like to make 375/400 hp
Re: olds 307 build
I think you'll find that the "3500 stall" converter will stall about 500 rpm LESS (3000 rpm) when its behind your 307 cid v8 VS if behind a 350 cid V8.. LESS engine torque = less max converter stall speed on launch.
You want to launch the car at or very near peak max torque output rpm. On a 307 cid hot rodded engine with single plane it is going to be 4000+++ rpm. (5000 rpm +/-)
4.56 gears good choice
You want to launch the car at or very near peak max torque output rpm. On a 307 cid hot rodded engine with single plane it is going to be 4000+++ rpm. (5000 rpm +/-)
4.56 gears good choice
Re: olds 307 build
You’ll need a true min 10:75 or better to get there.rocketracer380 wrote: ↑Wed Jul 08, 2020 10:26 pm 307 .040 offset ground crank 3.500 sj scat 6" rods 330 heads 54cc 1.875 intake 1.562 ex cam is solid 523" 530" 239 242 @50 106 lsa a holley street dominator and 650 carb ign is hei its goin in an 87 cutlass with a th 350 and 3500 10" appr 3400# 4.56 gears hopin for 12 sec et's i know just build 350 i'd like to make 375/400 hp
What crank are you using?
You might be better off with the perf rpm,, the Holley SD has very short runners which will hurt TQ on it...and the runners are a bit to big for 324”
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Re: olds 307 build
Those heads stock peak in Intake flow at .500" lift with about 180 cfm@28".
This could produce 370 hp but you would need far more valve lift and like a 12 to 1 compression to get to 370 hp!
Your going to need more then 4.56 rear gears also, you need to looking into the 5 something gear area.
Your going to need good valve springs also as the motor will need to buzz clean to a good above 7000 at which time a stock HEI module is well on the down hill side of what it can for firing rate wise.
This could produce 370 hp but you would need far more valve lift and like a 12 to 1 compression to get to 370 hp!
Your going to need more then 4.56 rear gears also, you need to looking into the 5 something gear area.
Your going to need good valve springs also as the motor will need to buzz clean to a good above 7000 at which time a stock HEI module is well on the down hill side of what it can for firing rate wise.
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Re: olds 307 build
When buying a "Custom" torque converter the stall speed has usually been designed to be correct for whatever engine / power level is being used
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Re: olds 307 build
True true if you can tell the converter builder how much torque @what rpm.. A engine dyno test is best. Otherwise they have to estimate the engines torque curve to get the converter build dialed in to get the desired max stall speed on launch.. A off the shelf "10" 3500 stall converter" will stall about 400 to 500 rpm LESS IF when behind a 307-324 cid engine.. If this lil olds v8 is using a single plane intake getting the real stall speed right is critical on this.Walter R. Malik wrote: ↑Thu Jul 09, 2020 10:01 amWhen buying a "Custom" torque converter the stall speed has usually been designed to be correct for whatever engine / power level is being used
Re: olds 307 build
If you can port the heads and get the flow up to the 225 to 230 cfm (in) and 150cfm ++ ex even with the stock valve size you'll do pretty good. The stock zs cast flow is pretty modest.. you can fix that. Get the real compression ratio up to 10-10.50:1 for 92 octane gas .
The Performer RPM manifold is probabily a better choice.
Its a lot like hotrodding a 305 or 307 chevy.
The Performer RPM manifold is probabily a better choice.
Its a lot like hotrodding a 305 or 307 chevy.
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Re: olds 307 build
I agree with the above posts
1 - You are going to have to get it breathing deep. Port the intake and the heads, you may lose torque with the single plane, but can drive around it on the drag strip. Get the heads working well, and the intake slightly better. I think you will find that the early intakes also have a low carb pad that hurts the direction you are trying to make it traveel
2 - Not knowing the rest of the cam specs, I also think you are deep into race gas territory with that cam assuming a 106 ICL. If that's the plan, good to go, but if it's a street car, you'll have to make some adjustments
If I were attacking this one, I would get the heads flowing as good as I can (or go aftermarket if available) prep the intake to match the heads. Then cam for the RPM range you intend to run, and pick pistons to support the compression I needed. I'd also do my best to go a light piston and modern rings to sneak every bit of power out of it
1 - You are going to have to get it breathing deep. Port the intake and the heads, you may lose torque with the single plane, but can drive around it on the drag strip. Get the heads working well, and the intake slightly better. I think you will find that the early intakes also have a low carb pad that hurts the direction you are trying to make it traveel
2 - Not knowing the rest of the cam specs, I also think you are deep into race gas territory with that cam assuming a 106 ICL. If that's the plan, good to go, but if it's a street car, you'll have to make some adjustments
If I were attacking this one, I would get the heads flowing as good as I can (or go aftermarket if available) prep the intake to match the heads. Then cam for the RPM range you intend to run, and pick pistons to support the compression I needed. I'd also do my best to go a light piston and modern rings to sneak every bit of power out of it
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Plattsmouth, NE
70 Mustang, 489 FE, TKO-600, Massflo SEFI, 4.11s
71 F100 SB 4x4, 461 FE, 4 speed, port injected EFI, 3.50s
Re: olds 307 build
If the measurements and cr calc is accurate its not that hard to tame the cr a bit so it can run on pump gas .
The chamber rework will likely also aid breathing.
The chamber rework will likely also aid breathing.
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Re: olds 307 build
The chamber isn’t prone to detonation...your good with that comp and premium pump
I’ve made 440hp&tq at 10.5 comp with the 307 and over 500hp 450 TQ at 11.4 with better fuel.. all under 6500
Heads only needed to flow 220 and 230 with a 2” intake 1.5” ex
Don’t over size the primary pipes..1 1/2 to 1 5/8” is fine
I’ve made 440hp&tq at 10.5 comp with the 307 and over 500hp 450 TQ at 11.4 with better fuel.. all under 6500
Heads only needed to flow 220 and 230 with a 2” intake 1.5” ex
Don’t over size the primary pipes..1 1/2 to 1 5/8” is fine
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