SR71BLKBRD

iTrader: (1)

Hey guys. recently my 700r4 died on my so while its down I planned on taking advantage of this to throw in a lt1 cam I recieved from a buddy as well as some 1.6 rockers, new timing chain set, lifters, springs, valve seals etc. I planned on porting the intake while i have it off as well as the plenum, runners and heads.

heres my question. i know the limiting factors are the runners and since they cant be ported much even with them gasket matched at the inlets, and the little notch beings smoothed out.with the stock runners slightly ported can i siamese the intake and the plenum? or should i just port the intake straight across and enlarge the holes as ive seen without siamesing. and what about the plenum. can i combine the holes or should i just enlarge them?

ORRRRR should i just enlarge the inlets to improve the flow and hold off on siamesing until i get a set of aftermarket runners?

also with these being done with all the previously mentioned mods will i need a prom burn? its a 91 Gta l98. with a Map sensor with the basics headers, 3" borla, 8mm wires.

could i get away with a aftermarket chip instead of a prom burn? I was looking at a PCM4less for a heads and cam chip. or should i stay with a stock chip and have it burned. im way to busy to try and take up learning how to burn a prom at the moment so it would have to be done somewhere.

with all that said and done. do you think it would be a noticable improvement? the cars great down low....im looking for high end.

any input is appreciated good or bad....lay it on me haha thanks in advance!

TTOP350

iTrader: (8)

I'm not sure the cam swap your planning is really worth it. I'd just slap the rockers on and be done.
I don't think you'll need a prom burned for this setup but others with more experiance will chime in im sure

BlackenedBird

iTrader: (5)

With a MAP car & that much mods? Yes if you want it to run to its potential. If if was MAF you can get away with more mods & MAFs will self-tune themselves, to a degree.

But it will most likely run & run decently, just not as well as it could.

Abubaca

iTrader: (3)

I agree that a MAP/SD car would probably need tuning. ....I also agree that an LT1 cam swap probably isn't worth the effort.

SR71BLKBRD

iTrader: (1)

alrighty then. guess i should look into having the prom burned then :/ ...any insight as far as how i should port the intake, runners, plenum and heads for the best gains?

Orr89RocZ

iTrader: (20)

Want some more top end, siamesing will be the key, but I'd just port the stock base around the head inlet port side, lay back the floor and raise the roofline abit, and try to find a set of SLP runners and siamese those an inch or 2. May not need a prom for this but there is a good bit to be gained with tuning so I'd atleast consider it. It be better if you got into tuning it yourself to get the most out of it.

SR71BLKBRD

iTrader: (1)

So ive heard however Im running 20 hour days with work and school monday through friday. only have the weekends to do anything. id rather just have someone tune it for me. although eventually i plan on learning when my load lightens up.

cuisinartvette

Can do all pieces if you like.
They take me awhile but if you dont need them right away shoot me a pm.
With porting imo its all out or nothing.

Abubaca

iTrader: (3)

There's a nice set of the cast aluminum Accel runners in the classifieds right now, FYI.

SR71BLKBRD

iTrader: (1)

I saw those accell runners I just dont really wanna cough up another $300 bucks. for the price is it really worth it?

Abubaca

iTrader: (3)

"worth it" is a relative term. I wouldn't bother doing much to any part of the engine (other than the basic free mods) unless I was going to upgrade the TPI. That means at the very least, aftermarket runners, and a port matched stock base, with a port matched stock plenum. Doesn't mean you have to do it all right away if budget is an issue (trust me I know!), but it should be part of the long term plan.