Verz

iTrader: (21)

So I have the chance to pick up some 853 heads with center bolt valve cover pattern fully assembled for a good price. The plan is to pick up a 6.0 block, couple new/machined blocks floating around, run it with a cam/bolt ons while I save up to add a blower on down the road. I know they are close to 241 heads but my questions is how would these heads compare NA and boosted to say 6.0 or 5.3 heads? End goal is to make around 500rwhp and low 11s in a 3500lb Dakota with a t56 and stock rods/pistons.

bww3588

iTrader: (49)

The 853's have smaller chambers than a stock 317. Also, some have the infamous pry notch that limits you to composite gaskets which are not optimal for boost. I would be on the lookout for a set of 317's. They have the same ports as the ls6 head and with the larger chambers and ability to run a better gaskets, they will suit your needs far better.

A little port and chamber work and they can easily flow as well as a ported 243.

Verz

iTrader: (21)

Preciate the feed back, 317s arent going to hurt performance while NA?

bww3588

iTrader: (49)

Depends. What pistons are you using? Lq4 or lq9?

With the lq4 pistons, your compression will be around 9.4, 10:1 with lq9's.

With boost the higher compression will hurt you while the lower compression will hurt you n/a.

If your looking for only 500 at the wheels, I would do it with heads, cam and compression. Easily obtainable with a 6.0

If you use the 63cc 241's or similar, you will have around 10:1 with the dished pistons and higher with the flat tops.

There is really no combination of parts that works well n/a and with boost unless its a stock setup which your only planning 5 to 7 lbs and even then it's not optimal.