blackey

iTrader: (1)

I know this question has been asked about a thousand times, but it seems like as vendors get a better handle on the new LS3 heads this answer might not be the same.

I'm building a 403 (4.07x3.9) road race motor. Power band must be good between 3500 and 6500. Anything below 3500 really does not matter.

Which heads will make the most power under the curve from 3500 to 6500?

I was thinking of putting stock LS3 heads with springs on the car and waiting for the new TFS/AFR heads due out later this year, but I already have a ported Fast 92/92 that I could use with the TFS/AFR heads from my current motor. Right now I do not have heads for the new motor at all (No cores)

So the options I see are these:

1. LS3 with new valve springs, mill to 65cc and wait. (About $1000 into them and another $325 in the intake, fuel rail and injectors - sell the Fast 92)

2. Ported LS3 with new valve springs, mill to 65cc and keep (About $1525 and $325 in the intake, fuel rail and injectors - sell the Fast 92

3. AFR225 or TFS 235 ($2200 and use the FAST92)

Overall I think the cathedral is going to cost about $1000 more, is it worth it?


Thoughts?

sixpack_2_go

iTrader: (1)

TFS is putting out new heads? where can i get info on them?
p.s. sorry to hijack the thread

hymey

I would look at the texas speed heads PRC 227 and with a stock stroke around a 232 intake lobe with a stroker and those heads a late 230s or better low 240s ie 244/248/112 with 11:1 comp would be great with that ci engine with those heads. Use a smaller port and run more overlap.

Fourman

i have moderately ported L92s on my 11.3:1 403 and made over 400tq from 2800 to 6800 rpm, peaking at 476. i dont have a huge cam for the combo, but shes got a good bit of punch everywhere in the rev range

edit: those are rear wheel numbers in an M6 GTO