what CR for a 306

aleborjas · May 12, 2006

hi i'm rebuilding my engine and i whant to know what is the best compression ratio for my combo to feed good my heads and headers because they are little big for my combo so what i have is 306 forged pistons, AFR 185's, 1 3/4 LT headers, 2.5 pipes til mufflers and 3" tail pipes, typhoom intake ported, 70mm TB, comp cams XE274HR, 30 pounds injectors and how many HP's can i expect from this at the wheel and at the flywheel....

jgfiveoh · May 12, 2006

10.5 to 11.0:1 thats right in the range i run. i would expect 280-300 wheels at least. good luck

aleborjas · May 12, 2006

how can i reach the 350's?

blue302stang · May 12, 2006

are you looking for 350 to the wheels or the crank, and is it a street car?

350 can be obtained N/A but will not be very streetable.

Grn92LX · May 12, 2006

What pistons do you have? Flat tops?

350rwhp is easily do-able but that cam isn't the right cam. Your heads and headers are nothing "too big". Keep what you have and work from there. If you have a good flat top piston and a zero deck block, just mill the heads as needed to get 10.5-11:1. Just keep in mind that if you mill a lot the manifold may not line up 100%.

5spd GT · May 12, 2006

Those heads are "to big" for a daily driver that sees different scenarios.

For what he wants, they aren't to big, since he appears to be going for track times.

350rwhp is easy if you want to take off a couple accessories and have a high revver (more than 6k) with high compression...

350rwhp is not easy at all if you want to keep your accessories and streetabilities...

Also vacuum from the cam effects your brakes...in general, the bigger the cam, the less vaccum...

With the "flat tops"...obviously p-v clearance might be close if you are going to start cutting on those heads...

Good Luck!

aleborjas · May 12, 2006

Grn92LX said:
What pistons do you have? Flat tops?

350rwhp is easily do-able but that cam isn't the right cam. Your heads and headers are nothing "too big". Keep what you have and work from there. If you have a good flat top piston and a zero deck block, just mill the heads as needed to get 10.5-11:1. Just keep in mind that if you mill a lot the manifold may not line up 100%.

my pistons are 4.040 they are SRP flat tops and the heads are 58cc's and i dont whant to change the cam because i whant to keep the A/C i whant to get the most HP's with what i have and some persons tells me that i have big injector and some tells me that those are ok so what do i do?i have stock rails and holley 190GPH fuel pump... should i look for 10.5 CR?

Grn92LX · May 12, 2006

I think you'll be happy with the combo. I'd like to see a little more gear but it'll make decent power for sure.

Not sure what changing the cam has to do with deleting your AC?

Do you know the specs on those pistons? I'm sure you'll be in the 10:1 + range. What you have is fine, just get it running and enjoy.

aleborjas · May 12, 2006

i mention the A/C and the cam because of the iddle

aleborjas · May 12, 2006

and the injectors are ok? 30's

85_SS_302_Coupe · May 12, 2006

I like 10-10.5 for pump gas, just in case you run into a lesser grade of gas.

aleborjas · May 14, 2006

i run 95 octanes here in my country and what about injectors? 30's?

what CR for a 306

aleborjas

New Member

jgfiveoh

New Member

aleborjas

New Member

blue302stang

New Member

Grn92LX

Fidanza Man!

5spd GT

"the 5.0 owns all"

aleborjas

New Member

Grn92LX

Fidanza Man!

aleborjas

New Member

aleborjas

New Member

85_SS_302_Coupe

it sucks (I know) to be on the receiving end

aleborjas

New Member

Similar threads

what CR for a 306

New Member

New Member

New Member

New Member

Fidanza Man!

"the 5.0 owns all"

New Member

Fidanza Man!

New Member

New Member

it sucks (I know) to be on the receiving end

New Member

Similar threads

Privacy & Transparency

Privacy & Transparency