Thread: 383 one more time

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some how the last thread got deleted , you guys were triing to explain to me how my cam was to big for my cr . 234/344 and 488/510 with 9.3:1 compression ,,,,, well u guys were saying i wouldnt have enough cylinder pressure , well i did a compression test and all cylinders were 165-179psi . so whats up on that just triing to figure this stuff out. cause 165-170 sounds reall good to me ,

You don't have to take anybodys word on anything- if you don't accept the advice you were given then just go ahead and build it.

Basically with the larger duration cams your effective compression stroke of the engine is reduced due to late intake valve closing. The guys are talking about dynamic compression when refering to low cylinder pressure. So what is done to compensate for this is you increase your static compression to make up for the lost stroke and lost low end power. I agree with the others with your compression and the duration on that cam you will suffer on bottom end power with your motor. You will never really make it up.
I would try to get at least 10:1 minimum with the cam you have.

i wasnt triing to rage on there advice , im just triing to learn why and how to fix problems , and i have already built the motor
thank for the good input 73RS

You can go to a roller cam with less duration and that will help your bottom end. In my 383 this is the cam that I'm using and for more lift I whent with 1.65 rockers on the IN(544) and 1.55 on the EX(519)

DAVE

you have two options, either increase compression, or decrease cam.... either way its gonna cost your come money, but more than likely the cam will be the cheaper way to go.... if you've got the funding though.... i'd get that compression up :-D