Speed_Kills

Would Trickflow's 215cc R heads be too big with a 240 duration cam?

bjankuski

The 215 are too big, the largest intake valve that will clear the 305 bore is 1.94" and the 215's have 2.08" valves. The heads that will fit are 180 AFR, the new trick flow 175 head, E-tec 170's, Vortec heads, and L-98 alum corvette heads. I am sure other will work but these are the performance heads that will work.

Speed_Kills

There's no way to make power with those small heads. Looks like i'll just be doing a superchargerd 5L instead.

bjankuski

How much power are you looking to make? Some of the heads that I have listed flow over 240 CFM at 28" of water which is good enough to support 500+ HP with the correctly built engine. What are your goals?

Jim85IROC

iTrader: (2)

There's no way to make power when your valves smash into the block deck either. When you choose to run a tiny bore motor, there are certain issues that can not be avoided. There's a reason that guys build 400s instead of 305s.

LAFireboyd

iTrader: (3)

According to its flow rates, the Trick Flow 175 should make excellent power.

Summit's site even says the GMPP Fast Burn heads fit a 305 too, though I think that'd be an awfully tight fit.

And playing on Desktop Dyno, both heads, theoretically, produce very similar results.

Flow rates for the GMPP head can be found at SBC Cylinder Head Info But the Trick Flow rates on this link are for the 195 head, not the 175. You'll have to go directly to Trick Flow's website for info on the 175 head.

Shagwell

215 cc on a 305???? what are you looking for about 18,000 rpm? That's the only way a small bore motor would ever use that much cfm....Especially a TPI, which would never flow to the heads.
- Larger heads DOES NOT = more hp. Too large of a head will lower hp and drastically lower tq, thus making much less power than a properly sized head. I'm running 11's in a 4000lb car with un-ported 200cc heads, what are you expecting?