mdtj

iTrader: (2)

I got a good deal on some LS7 heads with bronze guides for my LS3 416, I was wondering if I change out the exhaust valves to a 1.59" would this clear my pistons. Any info would help.

Camper

iTrader: (1)

arent you a little concerned with the bore?

mdtj

iTrader: (2)

Not really because tsp sale a small bore LS7 head that requires at least a 4.065 bore and I have a 4.070 bore. It look like all they did was a little more port work to them and change the exhaust valve.

dekan513

iTrader: (2)

ya small bores will work. ur other ? i don tknow

Camper

iTrader: (1)

you didnt say you have the PRC small bores? is that indeed what you have? or CNC LS7's?

mdtj

iTrader: (2)

CNC LS7's, I'm trying to see what needs to be done to get them to work on my LS3 416.

redgto4u

iTrader: (8)

I don't think they will....hence the small bore ls7 head for folks like us.

lil john

I think you can Call RED racing engine's in Colorado they did a engine with small bore and LS7 heads for engine masters challenge EXH valve was I think 1.560 I have the mag I'll go check.

lil john

Yea thats right bore 4.065 and 4.100 stroke GM LS7 heads 2.200 int. @ 1.560 exh. it is 2010 engine masters challenge.

good2go

Does this seem like a bad idea to anyone else but me? The LS7 heads are good, the intakes flow exceptionally well, the exhaust, not as well. That's why most LS7 cams have a large split, favoring the exhaust. Now you are going to put in a SMALLER exhaust valve, and shrouding it against the bore?

DietCoke

iTrader: (18)

PRC small bores have a different valve angle and valve spacing then LS7 heads.

lil john

To MDTJ: The last to threads hit the nail on the head. RED also shrunk the port to 256 cc stock ls7 port is what 270cc or 264cc without cnc machining.Check out LS3 heads Mast or buy TFS ls3 as I did for my 408 even though I bought mine bare.