GMPP L92 smallbore heads

[Batman]

GMPP just released a set of small bore L92 style cylinder heads, no price yet but the part # is 19201807. More to come!

[84ta406]

What makes them small bore? Smaller valves?

[Batman]

and smaller combustion chambers, they are for the 5.7 engines, regualr L92 heads need a min of a 4.000" bore

[84ta406]

The heads only have 70cc chambers to begin with, any clue where theyre at now for these?

[c4boom]

they have been out for a while like 6 months but no one seems to knows price or when they will be released

[Batman]

I don't know if the CC changed but the shape is different, more like an LS1 head. I think I heard they are going to be 67CC but can't remember. Mast already has some smallbore L92's but they are over $3000.00, I bet these come in at about $700 a head

[84ta406]

I looked at the Mast heads and theyre crazy expensive! GMPP makes some damn good shit.

[c4boom]

I wonder how they would do on a Ls1 with a 228 cam if the huge intake ports would kill the low end

[Batman]

I think they'd be a waste of money on a 228 cam. Stock heads can support that no problem

[Slowhawk]

Originally Posted by Batman

I think they'd be a waste of money on a 228 cam. Stock heads can support that no problem

That could go different ways.

I'll say the 228 Cam is too big for the heads.The catch with the L92 style heads is they flow a ton on the inlet and restrictive on the exhaust.Cam design changed alot with it.A big Cam will stall the air in the midrange causing a big loss of power. On L92 headed 402ci motors I run a 228/240 Cam and make mid 500's to the tire.This cam gained 40hp/40tq over a 236/238 Cam.

On a LS7 Vette we gained 35hp/35tq from 2k rpm to 6400rpm just running a 215/228 Cam.

Both cars drove like stock.