Bosko

Hey y'all! I am looking for some advice as I start planning my engine build. The car is a 1971 Mach 1 with a 351C. I want to use it as a fun daily driver, so I am looking for 450-500 hp with low end torque the priority. Preferably regular pump fuel (~87 octane). I'm afraid that my stated mission is contradicting basic physics.

Here's the plan so far.
1. Bore and stroke to 393, using Scat rotating assembly part 1-46235BE, which includes flat top pistons;
2. Edelbrock Performer RPM heads with 60cc chambers;
3. Edelbrock Performer Air Gap Intake Manifold;
4. Valvetrain TBD, but looking for a hydraulic roller set up;
5. Use existing Hedman headers with Pypes exhaust system.

I calculate the compression ratio with this setup to be about 12:1, which seems high for a mostly street engine. Can I use regular pump gas at this compression ratio?

The CHI 3V heads have a 68-70cc chamber, which calculates to compression ratio of ~10.8:1, which seems a bit more reasonable but the cost for these heads is hundreds of $$ higher.

Any recommendations? Hopefully y'all can give me guidance to avoid a potential big mistake, or encouragement to keep going!

Thanks!

andrewmp6

12:1 is kinda high for a street car you might be able to run pump gas but it will be 91 octane or higher.Or if you can get e85 where you are that might be a option for you.

kenash

Hi,
You might check out this calculator with special attention given to the "dynamic" calculations. Cam events can affect the working CR.
http://www.kb-silvolite.com/calc.php?action=comp

Good Luck

69mach1377

The aluminum heads will help a lot, but 12:1 on 87 seems a bit much.
The above posts are a good place to start.