Best cam size for my 327 with AFR 180cc heads?
I have a 327 currently with vortec heads. I plan on putting on AFR's 180cc Eliminator Street heads and swapping out the cam for a bigger one. I plan on keeping the compression under 10:1, and was hoping for 400 hp or more. Just curious as to which cams you might recommend.
you want as close to 10:1 as possible.
big cams need compression and rpm. very critical on a 327.
What cam is in it now?
car, gears , converter??? etc etc? Other engine details?
400hp is no sweat w vortecs on a 327.
right cam, compression, intake, carb, exhaust etc.
you got to rev it up a bit. ( converter, gears)
the afr 180 head will need pretty much the same supporting parts etc to get the power and performacne you want.
your cam is way too small (272dur .440" lift)
The 650 carb is marginally too small should be a 750. ( not that big a deal)
if this 327 has flat tops the real cr is probabily way too low 9:1 ish, now.
10:1 on a flat top piston 327 requires a 0decked block ( or thin .015" head gasket) and 58-60cc (shaved vortec heads)
your motor is probabily not even close to spec.
the EPS manifold will come up short. You want the rpm intake.
the best factory L-31 vortecs are the early production ones that came out of St.Catharines ontario . (#062) made before 2000.
the later ones from mexico are not as good. Porting wil fix them.
you pretty much jsut need to fix and optimize what you got.
The vortec heads are not your problem. they are 400+hp worthy in stock as cast form. May need a few valve train upgrades for the new cam thou.
Last edited by F-BIRD'88; 02-28-2012 at 11:30 PM.
The car is a 1967 camaro, 3.50 gears and a 700r4 tranny, 9 inch rear, I don't know which torque converter because the guy I bought the car from knew very little mechanical info on the car.
I'm assuming now that you've read my other post containing engine specs too. Also, I had read that stock vortec heads could only handle up to around .450 or .460 lift cams.
On the pistons, I was just assuming they were flat tops because once again, he knew hardly any mechanical info on the engine, but they could just as well be domed pistons. I just haven't got around to nor did I plan to tear the engine down unless I were to swap heads and a cam. The engine is a fresh rebuild also, according to the guy it was rebuilt 2 years ago.
Also, I don't see this engine as having that low of compression as it needs 91 octane and pings if you jump into it too quick, although I do have the ignition timing advanced and I haven't checked the cam timing but he could've had it advanced also.
Last edited by 67CamaroRsSs; 02-28-2012 at 11:40 PM.
Wether you use the vortecs or the 180cc AFrs, you will need all the same upgrades.
If you do burp for the AFRs special order direct from AFR w 58cc chambers or the cr will be too low. ( flat top piston). It is very unlikely this motor ha a dome piston as all common 327 domed piston will not clear a vlrtec combustion chamber without mods.
If you are not willing to bring this motor up to spec ( real compression ratio) the cam any cam won;t work.
ya a stock OEM vortec head has a valve lift limit around .460" lift. You can fix that. ( valve guide boss machining for more lift clearacne and aftermarket valve seals) You can do the spring seats and guide bosses all in one operation.
3.50 gears is not near enough You want 4.10-4.30 or 4.56 ( tall tires)
you wil need a high stall converter (3500-4200stall) based on a 245MM converter case for the th700r4.
www.converter.cc www.converter.com www.atiracing.com
cam isky 280H mega cam 201281
cam Lunati voodoo 60104
anything similar same .050" duration.
you need a true spec 10:1 cr, should have a 750carb and rpm manifold.
you will need all thses upgrades with the AFR heads too.
just casue it pings and knocks when you rug it does not tell you the cr .
It tells me the timing is all wrong. Get a timing light and correct the timing tab TDC , using a piston stop, for a start. The distributor will need to be recurved now and recurved again later with a new bigger cam.
( with the little cam you got there, you want 14-18deg initial at idle, 34-36deg at max mechanical advance.)
just dialing in what you got there now will make a huge difference.
EG the little cam you got now 272-440 ish needs a true 10:1 cr.
EG you need a 3000-3500 stall converter and 4.10's now just to be in the ball park.
do not bother buying a cheap modified 12" converter for the th700r4. They are a waste of time. Get the real deal 9" w lock up.
this motor is easy to get 400hp w vortecs.
you can get about 360-370 honest HP with the little cam once the rest is corrected. (13.0 to very high 12's if you are sharpe)
This could even be a 305 cid motor for all you know.
Last edited by F-BIRD'88; 02-29-2012 at 12:14 AM.
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