i've searched the forums and google for numbers from AFR LT4 heads, but i've not yet found them. I'm just wondering what dyno numbers anyone's achieved with almost any AFR LT4 head and what cam you used as well as what displacement. I'm just wondering what I'd need to get as far over 400rwhp/tq. as possible but still leave some headroom for bigger numbers. I was thinking AFR LT4 210 or 220cc heads possibly and a comp XE 227/233 cam would get past the 400rwhp/tq mark on a 355 spinning to ~6500+ rpm and leave room for additional porting later. Anyone have any ideas?

thanks

 

There is one guy with a 97 TA, that has afr 195's with a coustom cam from Joe Overton. It made 450rwhp and around 400rwtq. Considering it is on the stock bottom end, he's not doin so bad.
The 220+ cc heads your talking about are really big and are going to need more cam than the 227/233. If you want 400rwhp go with Llyod Elliot and his package or something from advanced induction. Both of them have two setups, the larger ones make great numbers. Plus for the cost of the heads alone you can get most of your top end. Check out AI online and email L.E. good luck

 

what do bare LT4 AFR 210 or 220cc heads flow anyway? i see the flow numbers on ported versions but none on the unported ones. I'm just looking for more headroom and i feel like stocker LT1 castings (after ported by AI or LE) will be maxed out the moment i get them. suggestions?

thanks

 

AFRs can be ported to flow into the 300+ cfm range, but then again so can GM LT4 heads.

 

Gotta be careful with large runners on a street car. They can really kill bottom end torque which makes the car no fun to drive. I'm not sure what non-ported AFR 220's flow, probably in the 260-270 range if I had to venture a guess.

 

Wrong.

Anyway. . .210 Race Ready heads flow ~280 intake ~218 exhaust out the box.

220 Comp's flow ~295 intake peak.

210 Comp's and 220 Race Ready's are in the middle somewhere.

I made 350 rwhp with a Carb'd 8.4/1 355 with 210 Race Ready's with a 234/242 cam. Same combo made 430 rwhp at 383 cid and 11.5/1.

Mike

 

mike - were those completely unported AFR heads? the bare castings that you used? or were they ported?

thanks

 

No one uses completely unported AFR's. The whole point of using AFR's is for the CNC porting. The flow numbers I quoted was for AFR's Race Ready and Competition CNC porting, respectively.

Mike