Transam1

iTrader: (6)

Hello everyone, i have AFR225's that have been milled to 59cc and a Trex cam at the moment and i can not get enough PVC (only .025) even with .085 valve reliefs cut into the pistons. So i called Thunder and they suggested the RapTR cam. It was hard to give up the Trex but i think its either that or different heads.
1.) Do you all think this is a good call on my part? It a full both on Trans Am, injectors, fuel pump, LS6 intake, underdrive, all that stuff...automatic, with 3600 or 4400 stall options
2.) A guy on here offered to trade me for 66cc AFR205's also so that is an option, but i doubt they will clear also.
3.) what kind of numbers could i expect and or track times, 1/8 mile with the 225's and the Raptr? anyone have similar set up?


Cam specs:
" RapTR" - 236/242 - .615/.615 - 111 lsa 3000-6800 RPM Power Band. Great mid-range & high RPM power. Requires computer tuning, 3600 converter on autos, 4.10's or greater depending on transmission. Works very well with nitrous and proper tuning. Due to the fast ramp rate of this camshaft, the use of 1.8 rockers is not recommended. Due to the extreme nature of this camshaft, piston to valve clearance must be verified when using modified cylinder heads.

kinglt-1

iTrader: (26)

Get a custom grind cam spec'd for those heads...problem solved!

butler

I have manley pistons that have valve reliefs cut in them but am using the same heads milled to 59cc. No issues.

brian_rs/ss

personally would've gone with 205's and a custom grind but that's just me. i'de also consider finding a FAST to top it all off.

Transam1

iTrader: (6)

why is that? why downgrade to a 205? car will be used mostly as a weekend warrior

Always2Slow

iTrader: (8)

because the 205s are not inferior in any way they are just for a smaller motor. You cant base cylinder heads on flow alone, ill give you an example. If you take a straw and a 4 inch pipe, the 4 inch pipe will flow tons. Now i say see which you can drink a glass of water the fastest with, the straw probably will win. The 205s are a perfect head except the valve angle for a 346 or so cui motor. The raptor cam will be a very nice cam for you and will make similar power to the trex but have a little bit more torque at the bottom of the gear.

brian_rs/ss

205 is not a down grade. it's just a shorter intake runner, which better suits a smaller bore/stroke motor like an ls1. why do you think patg used 205's for his 500 rwhp build?

https://ls1tech.com/forums/generatio...heads-cam.html

Transam1

iTrader: (6)

if you copy other people you will only be as fast as them.... on AFR's website the 225's flow better across the board and even in his writeup he says there was only a few hp different in my favor...so what the hell ill try

A.R. Shale Targa

iTrader: (2)

Larger runner heads are usually flowed on a 4" bore fixture.....not accurate
for a 346" 3.89 in. bore engine.....the object is to get the most flow
possible out of the smallest runner possible= the most efficient mixture
remember heads are flowed for air volume and the 5.7 liter air pump
injests air AND fuel.....mixture homogenaety is when the surface area
of thousands of fuel particles is greater than hundreds of droplets
the same reason you leave intake runner surfaces rough because of
boundary layer dropout....airflow quality is important even with a fuel
injector

Transam1

iTrader: (6)

ummm what? haha i understand most of that.

intenseblue

iTrader: (1)

The 225s will make more high-rpm power. Probably what he's after considering he went with the T-Rex

intenseblue

iTrader: (1)

T-Rex's are designed to clear on stock 66cc heads. AFR 66cc heads are supposed to have much better clearance even with larger valves.

If it were mine I would run the AFR's that you have with the Raptr.

garygnu

talk to Tony Mamo or Patrick-G for a custom cam that will work .