Piston to valve clearance - 454 Mag short block
#11
BEACH PARTY / HOLLOWPOINT
Platinum Member
Thread Starter
Tom, I don't think you will have an issue with flat top or small dome pistons and a 731. I am running a cam with .596 / .612 lift and similar duration to the 731 with flat tops, and it wasn't even close to interference. No need to go larger than 2.19 / 1.88 with the relatively small bore of a 454 block, from what I have been told.
Also, this is going to be a blown setup. I don't think the 2.19 intake will hurt it. Agreed that the 2.19 works much better on the smaller bore of the 454.
#12
Registered
Tom knowing what I know in my opinion anyone building a marine engine if it be a max effort or a mild "warm up" would be foolish not to buy a cam from Bob. I've had some lengthy technical discussions with the man and believe me his depth of knowledge goes much farther than what most of us know. If you are trying to get everything out of the combination you have his camshaft is the only way to go.
#13
BEACH PARTY / HOLLOWPOINT
Platinum Member
Thread Starter
Tom knowing what I know in my opinion anyone building a marine engine if it be a max effort or a mild "warm up" would be foolish not to buy a cam from Bob. I've had some lengthy technical discussions with the man and believe me his depth of knowledge goes much farther than what most of us know. If you are trying to get everything out of the combination you have his camshaft is the only way to go.
#14
Registered
Does anyone have any proven data that shows a 2.19 valve works better on a 454 than a 2.25? What cylinder heads are we talking about here? A small oval or GM rectangle port, or aftermarket rectangle port?
#15
BEACH PARTY / HOLLOWPOINT
Platinum Member
Thread Starter
I read where a guy did some flow bench testing, and by simply moving the head over some on the stand was able to gain 12 CFM. The context being that moving even the 2.19 valve away from the cylinder wall picked up some airflow.
Last edited by TomZ; 11-25-2014 at 08:26 PM. Reason: Clarity