Aftermarket Heads - CNC vs As-Cast for FI?
10-04-2013, 01:27 PM
#15
I am just wondering on an as-cast version, when they cnc the combustion chambers and do the valve seats, are the bowls blended as well? Would an as-cast runner be more or less consistent between all runners as a CNC'ed runner? (This is an issue I think I am currently having with my hand ports is #2 is getting significantly more air that the others.) These are the biggest concerns I have with an as-cast in a force induction setup.
Thoughts??
I am still undecided on the head I want to run but the as-casts are not off the table as of yet.
10-08-2019, 10:05 PM
#16
old thread, but a few years later I can add to the thread.
My most recent combo is a 408 with a kenne bell 3.6. I went from stock ls3 heads to the as-cast PRC 257cc square port heads. I lost 3 lbs boost, and had to add 3% more fuel at 15lbs boost at the same commanded WOT AFR. I'm not a tuner so I dont know exactly what it means...just what i had to do to maintain commanded AFR. I run Dominator EFI with dual widebands so my VE was within .2% before pulling the stock heads.
the CNC porting just wasn't worth the extra $800 for an extra couple ponies. bang for buck just wasn't there, and it's not a max effort build.
My most recent combo is a 408 with a kenne bell 3.6. I went from stock ls3 heads to the as-cast PRC 257cc square port heads. I lost 3 lbs boost, and had to add 3% more fuel at 15lbs boost at the same commanded WOT AFR. I'm not a tuner so I dont know exactly what it means...just what i had to do to maintain commanded AFR. I run Dominator EFI with dual widebands so my VE was within .2% before pulling the stock heads.
the CNC porting just wasn't worth the extra $800 for an extra couple ponies. bang for buck just wasn't there, and it's not a max effort build.
10-09-2019, 07:41 AM
#19
Truck Corvette Camaro Tuner in Tampa E85
I remember when I was building my C5 Corvette in 2004, Everyone was running truck heads because they offered more compression. The problem was, the valves are smaller so the headers didnt breath as well.
So the truck heads can be great heads, but will need larger valves to flow good air.
I ended up going with AFR 205 heads ( I dont think they make them anymore). At the time cost about $2500.00. Now you can pick up good aftermarket heads with springs on them already for about $1500.
Ive seen plenty of good builds with the TSP PRC heads and springs.
Phil
So the truck heads can be great heads, but will need larger valves to flow good air.
I ended up going with AFR 205 heads ( I dont think they make them anymore). At the time cost about $2500.00. Now you can pick up good aftermarket heads with springs on them already for about $1500.
Ive seen plenty of good builds with the TSP PRC heads and springs.
Phil
Last edited by 1FastBrick; 08-02-2023 at 01:45 PM.
10-09-2019, 11:06 AM
#20
Since the thread was dug up... I decided on a set of TEA's TFS235 with nitrous exhaust ports. Ended up with a set of 245's and was convinced to keep them. With the new cam and heads, boost decresed by a couple pounds but power remained pretty close. My takeaway is the head will dictate boost level but ultimately with a supercharged application, the supercharger airflow will dictate the final power. If I were to do it over again, I would have gone with my initial instinct of 225 as cast TFS or PRC heads.
Thread
Thread Starter
Forum
Replies
Last Post
