Timberland

I have a PN# 12561184 intake. If my web search is correct its a LS6 intake. It also has by my visual look Rectangular ports. I have a pair of "799" casting heads, again by internet search are LS6 heads. By visual look have Cathedral ports. I'm now a confused old guy trying to figure out WTH I need to mate the two. I *thought* all LS6 intake and heads had the same intake mating port. I'm building a restomod '55 Chevy with a LQ 6.0 and Tremec 6 speed....... ol' mans car, lol

codyvette

iTrader: (24)

It does look a little off when you are used to looking at old school small blocks but what you have mates up great. Bolt it up and roll.

Timberland

How in the hell does it flow? My old big block Chevy days, it was a sin to mis match Oval port and Rectangular port intakes and heads. Now its ok to mismatch these Cathedral and rectangular ports???

Second question...WTH is the difference between LS1 and LS6 intake gaskets??

http://shop.advanceautoparts.com/p/f...intake+gaskets

http://shop.advanceautoparts.com/p/f...intake+gaskets

ScottyBG

If you look at the head, the pointy area at the top of the port lines up with the injector. Originally the LS cathedral head got the cathedral shape to allow the fuel injection to shoot fuel into the inflowing air stream more efficiently. Old school it was all designed around carburation, and airflow (air with evaporated fuel in it) as the only consideration. If you consider the head, without the "gable peak" on the port for the injector to shoot fuel in, the rectangular area of the head and the intake match quite well. So the addition of fuel injection, as a new technology, changed the way of thinking regarding matching head and intake ports. On a BBC the cross sectional area of a rectangular port is considerably different, than an oval port, and flow very different. The ports in your LS6 manifold flow appropriate amounts of air for the ports in your LS6 head.

You still don't want to try and put an LS3 or LS7 intake on a cathedral port head, that truly is a mismatch, because the volume of the ports are so different.

I've used both LS1 and LS6 O-rings on both manifolds. I've never taken the time to measure them? I didn't know they were any different? I'm guessing there may be a slight size difference. Since you have an LS6 intake just order the LS6 ones and go with it.

Nice Shoe Box, I'd turf the leaf brings and get an Art Morrison rear clip with the 4 bar, and coil overs though. Newer, better technology, for the back end, just like the nice tubular A-arms and coils you have put on the front. You gonna put a rack and pinion on it? or stick with the old Saginaw system? Either way, I love your project.

wannafbody

iTrader: (2)

The intake you have is a square port LS3 intake. You need 823 heads to match with that intake or your 799 heads to match to a LS6 intake.

farmington

iTrader: (14)

It is a cathedral intake. No doubt.

wannafbody

iTrader: (2)

You're right, my bad