MUSTANGEATER

iTrader: (10)

Assuming that I could run the same level on compression due to piston selection which head would be better for a Naturally Aspirated/Nitrous 347 Motor?

Are there any Pro's of going to the 6.0 Head besides price? What about Con's, could the larger Combustion Chambers lead to any problems?


Thanks

Floyd

VINCE

iTrader: (1)

I personally think the 6.0L's are hard to beat. Like you mentioned you should be able to get the same compression with piston selection. According to test TR did awhile ago the 6.0L head showed better low to mid lift #'s than the LS6 head, but the LS6 head outflowed the 6.0L head in peak airflow, but not by much. These test were done on stock 6.0L and LS6 heads if I remember correctly. I am sure a good head porter could get the 6.0L heads to flow identical to the LS6 heads peak and still outflow in the low to midlift areas. For my FMS 409ci build Futral suggested I go with 6.0L heads for two reasons. Lower price and the 6.0L heads can perform just as well as the LS6 heads up top with a proper port job. You can use the money you save by purchasing the 6.0L heads towards something else. Like the new LSX or a direct port nitrous system.

MUSTANGEATER

iTrader: (10)

Thanks for the Reply. I was going to give FMS a call about a few things anyway I guess I'll talk to him.

TTT need some more opinions though

Brian Tooley Racing

iTrader: (13)

I have done back to back testing on our flowbench with our Judson Stg 2.5 (for a 2.05 valve) on a LS6 head and a 6.0L head, they both flowed right at 325 at .600" on a 4.030" bore, but on a 3.90" bore the LS6 still flowed 320, and the 6.0L was down to 309. It is because of the lip at the top of the small bore. If you have a 4.00" bore engine go with the 6.0L, if it is a 3.90" bore, the LS6 will make more power. We recently did a set of these LS6 heads for Ron @ GMMG and they made more RWHP and RWTQ then any head they have ever tested, and he has an archive of almost 100 dyno sessions. This is the same head I put on my car and picked up 90 RWHP on the same shot of nitrous, over our 5.3 heads. Here is a link to the thread with the graph, and a link to my nitrous graph. Hope this helps.

https://ls1tech.com/forums/dynamometer-results-comparisons/135762-tea-ls6-stg-2-5-heads-448rwhp-433rwtq.html

https://ls1tech.com/forums/attachmen...achmentid=3560

VINCE

iTrader: (1)

It sounds like that extra 700 to 800 bucks for the LS6 cores is worth an extra 11 cfm peak. What were the low and mid lift #'s on the 3.90 bore Brian? How much do 11 cfm equate too horsepower wise?

MUSTANGEATER

iTrader: (10)

That's an interesting point you make, how much of a horse power difference would the extra 11 CFM @ peak be? and is there any mid lift loss?

Right now it looks like a 347 w/ 11.5 compression with either head would run great but I'm still searching for answers. What heads are all the 9 second 347's running? LS6? 6.0? 5.3? and of course who ported them