Ok I am trying to get my head rapped around what to do with the head gasket thickness and push rod lenght.

I already have 243 heads (non zo6) stock lenght valves and an ls6 cam 02 (smaller base circle) from my under standing if I use stock gasket thickness and 7.45 I should be fine, but what compression will be running with the smaller combustion cambers that the 243's have and the ls1 pistons? For now I would like to stay close to stock as I can if I even need to. Also if I do go with the higher compression what are the pros and cons?

Other mods: LT, ORY, catback, lid, and p/p t/b (no stall yet)

If I am incorrect about anything let me know.

 

i am tearing my ls6 down now i will meassure next week pm and remind me

 

Did you get different length pushrods? Or was there no need since you are using non Z06 length Valves?

 

do you have the hollow valves

 

No not yet thats why am asking so I no what to get. if I have to ill just do the 7.45 p/r but I am curious about the pros and cons of the higher compression.
The the 7.4 will be to short so cant just reuse them (didnt want to anyway)

 

Check your pushrods...I think you will find the 7.400 rods are the ones you want to use. I just did this conversion and that is the length that fit perfectly. 7.450 is a HUGE change.

 

really? let me ask you this did you have the true ls6 heads and also did you use the factory head cover thickness? and did you use an older ls6 cam or an 02 up? the base circle on the 02 cam is .05 smaller so it makes scince to have the longer ones.

 

granted my GTO has a LS6 block..... but i used unmilled 243's 7.4 pushrods and factory head gaskets for my H/C job..... runs like a champ...

 

^^ did you use an ls6 cam or an aftermarket

 

For going from 10.1 to 10.5 compression there will be no downsides. If it were me I'd go ahead and get a decent cam/spring/pushrod setup to do with those heads

 

Well if fed ex didnt jack up the first cam and loose the push rods all together that I bought (im still in claims with them) along with some other things that took money from my car fund( I was going to do a stall aswell) I would be doing that but i just cannot save back up fast enough i have 11 day off of work first of june and i do not want to wast it. Considering ill be going from a stock ls1 with a lid and catback
to basicly an ls6 with LT's and cut ou,t p/p t/b (along with the free mods I have not done yet) I should still pick up a few tenths in the 1/4 I loooooove working on my car so if I had to do it again later ohwell but its going to be awile anyway im going to do susp. tires, rear and stall before I dig back into it if its not ready to be rebuilt anyway.

 

also the car is a dd

 

crap im probly thinking 7.425

 

I am using a true set of 243 LS6 heads, but without the long valves.

I am using a genuine GM head gasket that I believe is part number 12589227. That was the thickness I could live with for a helluva lot better price than a Cometic, etc.

I am using a Comp Cams 54-456-11 camshaft that is ground on a small base circle. My understanding is it should compare to the cam you are using as far as base circle is concerned.

I am using new genuine GM lifters and Comp Cams Hi-Tech 7.400 push rods...stock rockers...Comp 918 springs...stock retainers and keepers. I did use top hat seals, but that has no bearing on this.

I would bet the farm my son's 05 LS6 in his CTS-V has 7.400 pushrods in it.

This is all very interesting to me because I am seriously considering going to a 7.375 push rod. Shorter instead of longer. I like my pattern across the valve, but I want to try and reduce my lifter preload a bit. It's right where everyone says it should be (1.25 to 1.5 turns of preload) but I want to try and reduce that and see if I can't quiet up the valve train a bit. The radical ramps cause most of it, but it's worth playing around with just to see.

 

You know, a very wise investment would be a pair of adjustable push rods and check springs. Get the good push rods that are .050 per turn. Makes it easier.

 

From what I have read they do, the longer valves make up for it.
Also adj. push rods have crossed my mind

 

I had ls2 243s, 02+ LS6 cam, stock springs and I used 7.4 pushrods. Went into the 11s n/a

 

See im not the only one who gets it. If I can hit 12.5-12.7 range witout a stall and D/R's ill be happy

 

If you just go with a stall first you can hit that same number! I ran 12.4 with Bolt ons and a circled 4c. But in south Texas we are pretty close to sea level.

 

We are here too I think around 200