I am building a budget 400 for my 77 firebird and need some advice, i have a 73 400 block, i am reusing the stock rotating assembly but am ditching the 4x heads for some higher compression ones such as #16 heads or 670's or something, so first i am wondering around what the compression ratio would be with say around 70cc heads with the stock pistons, and which cam i should use, i want to get a cam with the most duration possible for a nice choppy idle but without negatively affecting engine performance and also if i use a hydraulic cam can i use roller rockers? and what ratio rockers and what valve springs?, pushrods? i also plan on balancing crank and a little head porting and i have a performer rpm intake
400 build help
- Thread starter TDem73
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If you look at this chart you will see they have not used 70CC heads since the 60's because you will end with a very high compression. For the typical maximum RPM that a Pontiac will see roller rockers are not worth while, try the roller tip rockers. Download the cam selection software from Competition Cams and see what suggestion they make. They will also list compatible springs and pushrods
http://www.wallaceracing.com/head1.htm
http://www.wallaceracing.com/head1.htm
Zimgxp
New member
Roller rockers can be used with any cam. With a roller cam you need roller lifters.