I would think you'd make more power with the GM Fastburns since they have bigger intake runners, not sure what the flow numbers are on each though.

I have a set of Etec 170's on my 383 and my car runs awesome, lots of power and torque, etc. Makes great power right up to 6500RPM.

The ZZ383 crate engine GM makes utilizes those fast burn heads and it makes 450hp and is supposed to be a pretty wicked engine. I've heard the cam in that engine isn't too radical though (tame idle, etc). If you're going for the sleeper approach it might be worth it to try and duplicate the ZZ383 as it supposedly has a stock sounding idle but makes wicked power.

 

GMPP Edelbrock Dart Brodix Vortec World
Fast Burn Rpm 200 Track-1 L31 Sportsman II
Valve Lift Intake
0.100" 62 66 60 60 58 65
0.200" 136 135 124 130 114 121
0.300" 187 186 180 178 173 177
0.400" 232 215 221 223 216 210
0.500" 266 220 254 256 225 212
0.600" 275 222 261 259 222 225

I should add E-Tec 170 head flow:
Valve Lift .100" .200" .300" .400" .500" .600" .700"
Intake 64 130 186 220 232 238 -
Exhaust 54 104 140 169 183 190



GM Fast Burn all the way......Sorry about the lay-out, that is as good as I could get it. Jack

 

will the change in heads effect driveability at lower speeds?
stick with ZZ4 cam or other?

 

will the change in heads effect driveability at lower speeds? stick with ZZ4 cam or other?

Everything is a compromise....If you want a max street light to street light power range with a stock sounding idle, a good rule of thumb is go with a good flowing smaller port head and a smallish to medium cam that will meet your estimated power range keeping the port velocity high for max torque. If you want more power in the mid and upper range then go with the larger port FastBurn heads and the Hot Cam or something close that to increase the overall power range. The 383 small block really likes a 195cc head on the street and so the FastBurn fits right in. Either way it will still be fun to drive. I added the port flow for the E-Tech heads to my first post. To pick a great street head choose the one that has the smallest port that out flows the prospective choices in the .300 to .400 lift range. (Compare the flow numbers I posted) AFR dyno tests have proven in a 383 they loose just a little torque in the 2,000 RPM and below range going from the 180 to 195 head but produce more torque and power over the 180 head from there all the way to peak power. The Hot Cam has a more aggressive idle sound than stock but is a great cam. From GM Direct:
This head (Fast Burn) is a bolt-on 30 hp increase when used on our ZZ4 crate engine. When tested on a 383 ci small block engine with 9.5 to 1 compression ratio and .540" lift roller cam, single plane intake manifold and 750 cfm Holley carburetor, the Fast Burn heads produced 497 hp at an incredibly low 5800 rpm. With a RPM duel plane you will pick up a significent amount of torque and HP throughout the Curve but will loose a little very top end power. Like I said in the first post "Fast Burn all the way".....

 

I agree with 1320. I have 220s on my 421 and it has crazy tq and pulls hard to 7500+. I could actually benefit from a bigger head given the size of motor I'm running. But I wouldn't go any smaller than a 195 runner. And buy a good head and do it once...I have afr's and they are far worth the money.