Posted By: Cab_Burge
Blown 440 motors on the street, how much boost and compress? - 12/30/20 11:12 PM
I've got a customer who has a BDS 8.71 blower with two four barrels on one of his street pump gas 440 motor cars, it had a valve train failure and I'm getting to fix it for him I didn't build this motor originally
I've built blown pump gas hemi, BB Chevy and SB Chevy but no Mopar wedges.
My question to you that have built and driven them is what static compression ratio do you have and how much boost on pump gas?
This motor did not have a boost gauge so the customer has no idea what boost it was making, I'll fix that for him He has a 30 tooth and a 32 tooth pulley on the motor which according to my calculations is right at 6.2 % ratio under drive or over drive, am I right on this math
The old combination was stock stroke with 906 heads with right at 8.8 to 1 compression ratio, he wasn't happy with it and wants it to have a little more power and better tire spinning power for burn outs after the local cars shows are over
I'm planning on better new aluminum heads with 440 intake port size to be able to reuse is his current blower intake manifold and increase the cubic inch to 505 C.I.(4.350x4.250)and probably increase the compression ratio to between 9.2 to 9.5 to 1 ratio, what say you about these thoughts
Thanks in advance for your help and comments
I've built blown pump gas hemi, BB Chevy and SB Chevy but no Mopar wedges.
My question to you that have built and driven them is what static compression ratio do you have and how much boost on pump gas?
This motor did not have a boost gauge so the customer has no idea what boost it was making, I'll fix that for him He has a 30 tooth and a 32 tooth pulley on the motor which according to my calculations is right at 6.2 % ratio under drive or over drive, am I right on this math
The old combination was stock stroke with 906 heads with right at 8.8 to 1 compression ratio, he wasn't happy with it and wants it to have a little more power and better tire spinning power for burn outs after the local cars shows are over
I'm planning on better new aluminum heads with 440 intake port size to be able to reuse is his current blower intake manifold and increase the cubic inch to 505 C.I.(4.350x4.250)and probably increase the compression ratio to between 9.2 to 9.5 to 1 ratio, what say you about these thoughts
Thanks in advance for your help and comments