I'm running a set of stock ported early lt1 heads now. they flow about 258 intake side. Using GM847 cam through a 6spd. My current power numbers are 350rwhp/350rwT on a 358ci LT1, unported intake.

I'm thinking of upgrading the heads to AFR 195 or 210 and going with a ported intake.

Does anyone have any before/after head swap info or any opinions as to which heads I need to be looking at other than AFR?

I would really like to get closer to 400rwhp NA if I could do it, but reasonable I would be happy with 380.

 

Ported stock castings by AI or LE would get you your 400whp mark easily. Maybe consider ditching that cam too for something custom as well.

 

I agree, stock heads, properly ported will get you to the 400 rear wheel horsepower mark fairly easily. I disagree with Joe, though, on the cam. The GM 847 cam is more than capable of reaching 400 rwhp. In fact, I'm surprised you aren't there already. Perhaps you could tell us about your supporting mods and about the tune you had done. My gut feel is you can get there with what you already have...

 

I should point out that I mentioned getting rid of the 847 because if he goes with one of the big two, he can get a cam ground to fit the heads and make making and surpassing his goal even easier. The 847 will work, but if he wants that little extra, a custom grind is always a good option. Either way though his 380whp goal is pretty modest; either one will get you there.

 

AFR 210's are better suited for 383's. They can work on a nasty 350-358 but you'd want to run a big cam and spin it up near 7k to make the most out of it. Our pcm's poop out at 7k. The 195's would rock on a 350-358 cube motor.

 

http://elliottsportworks.com/?page_id=32

 

To give you an idea of AI's work...my car put down similar numbers to yours and I am running a very small emissions cam and an auto.

Their 200cc heads are fantastic.

 

I would just throw a set of Ai 200cc heads on it and be done with it. That should put you well over 400rwhp.

 

I should have included the head specs I already have that way you could get a better idea of what I have.

Casting: Early LT1 (casting 643)
Intake Runner: 180cc
Exhaust Runner: 66cc
Chamber: 55cc

Intake Flow @28" - 2.02" Valve
.100 70
.200 132
.300 178
.400 219
.500 250
.600 258

Exhaust Flow @28" - 1.60" Valve
.080 57 (67@.100)
.160 98 (110@.200)
.240 120 (137@.300)
.320 144 (165@.400)
.400 165 (180@.500)
.480 178
.560 185

Just figured you may want to see these numbers.

I appreciate all the feedback. I think I'm going to end up getting the AFR 210cc Competition Heads for several reasons.

One they flow great, two, I can increase the combustion chamber size to 65cc which will help lower compression for a supercharger in the future (I'm currently at 11:1, would take me down to around 9.8:1), and I have also been considering a larger stroker bottom end (383 or 396) and I think they will be the best overrall choice.

 

Who did the portwork on the heads you have now, and how do you plan on increasing the combustion chamber size?

I can't say I have ever heard of anyone going from 55cc to 65cc ! Not saying it can't be done...just saying I never heard of it. Also, I'm not sure if AI will port heads that someone else has already had their hands in, you might wanna email them and ask.

Me personally, if that really is your goal, talk to AI about their TFS 215 heads. Those will come with bigger combustion chambers. Oh, and dropping your compression to 9.8:1 is not gonna help you reach that 400rwhp goal. Not N/A anyhow.

 

I think he means he can order some AFR 210 heads with a 65cc, increasing from the current 55cc he has?

 

Ah ok. I must have read it to fast/wrong. My bad.

 

Look at the Advanced Induction ported Trickflows.

 

If your looking to do it right. No short cuts. AFR's or the Dart heads will get the job done with out worry of cracks or other b/s. Mismatch ports, or other problems. Contact them and some cam companies for info on heads and cams. They will help you chose the right cam and head combo to match what you want to do. I have comp port AFR heads and are just perfect. I only thing is You have to use the right header gasket. A stock LT1 gasket is way to small and the Felpro 1470 is not big enough. I use a Felpro 1406 which is for Brodix heads. AFR recommends Felpro 1404. Also make sure your headers match the exsaust ports of the heads otherwise it will lose power. I see this mixmatch all the time. Also porting the LT1 intake is a must to get the most power for the match. You'll be very happy..

 

Oh yeah the 210cc AFR will be very happy with the 383-396.. Supercharged, turbo, spray. They can take anything you throw at them. Also have a lifetime warranty. Stock ported heads can't say that, and that speaks volumes