1972nova

iTrader: (13)

Would I be ok with 317 heads on a 5.3 with 01 ls6 cam? I have heard from some that the compression would be too low.

I am going mpt70q or mpt76

black98ws6ta

iTrader: (77)

Compression would be fine, but it wouldnt hurt to mill the heads. The e85 takes the need for the compression drop away.

IT_SS

iTrader: (5)

not to bring this thread back from the dead, but what if you decided to run with untouched 317 heads? What would the advantages be? I ask because I'm a bit on the fence about e85 vs 91 and meth for kill. Despite E85 allowing more compession (w/ milled heads), will it also allow for more boost/timing on the existing 5.3 317 combo?

Grr

iTrader: (2)

if you plan on running E85 i dont like any LESS than 10:1 compression. On a small bore 5.3 there is no way in hell i would lower the compression, with a bore size the 5.3 has i would like to be closer to 11:1. In this instance at 11:1 it would be pretty much identical to a 9-9.5:1 engine on pump gas, but with a little more cushion. Just my opinion.

IT_SS

iTrader: (5)

so E85 is only beneifical on higher CR power plants?

skinnies

iTrader: (33)

I'm not sure why the 317's would be used, just use the stock heads and a bigger turbo, I'm running the aluminum 5.3 with the stock heads so a little more compression with a TC78 and made 686rwhp on 18lbs on e85.

NicD

iTrader: (7)

No, it's just more beneficial. It's still a higher octane fuel and all the benefits that come along with it regardless of compression ratio.

IT_SS

iTrader: (5)

Skinnies- I hear you man, but I only have a 5.3 short block, and 317 heads. I'd LOVE to run a set of 243 heads, but I figure I'd just up the boost. Now that I think of it, can the 2002 PCM/ECU handle E85?

NicD - Thats whats I was thinking

Thanks all

71 chevy

iTrader: (18)

from everything Ive heard and read, e85 allows more timing, more boost, and more compression compared to pump gas. it also spools the turbos a faster, and makes more power even at the same boost setting as pump gas.

IT_SS

iTrader: (5)

and my understanding is that with speed density tuning I can run two fuels on the same tune? Here in Los Angeles, my understanding is that we only have 1 E85 station, so 91 will be used for normal driving

pwrtrip75

iTrader: (8)

Where did you hear that? BS.

mwg2600

You can run different boost leavles on the same tune. If the tune is set up for ill say 28lbs you can run 10 pounds on that tune if its set up for it.

IT_SS

iTrader: (5)

got cha. Two Fuels = Two Tunes

180ls1

iTrader: (4)

stock ls1 heads are an option also, that would put you compression and flow wise inbetween 317's and 706's or whatever 5.3 heads are and it will keep your budget in check.

IT_SS

iTrader: (5)

I do have the 241s from stock LS1.....