SpinsB

iTrader: (5)

here is what I have. resleved ls2 ported/polished ls1 heads 244/244 612/612 mti s1 cam 90/90fast 1 3/4 headers 3" y pipe gmmg exhaust. numbers came back at 455/460. was thinking and wanting over 500. all thru a m6 car peaked quick at 5800-5900. Guy that did the tuning and dyno said it makes it power quick.

with that said I know there are better heads and maybe even a diff cam that would get me there. I just dont know where to start. any info would be apperciated

sergo

it's not breathing worth a damn.

SpinsB

iTrader: (5)

so bigger lid maf tb intake headers...?

oChristiano

iTrader: (6)

1 7/8's headers FAST 102 bigger lid n maf and most importantly...better heads.

SSPerformance

iTrader: (76)

who ported the heads

Brad Hutchcraft

iTrader: (8)

Do you have any shots of the graph or any other information from your session? There is a lot to guess at here.. At first thought, yeah, I would guess the heads are holding you back. But we need more information to give you a better idea where to start. Any more information on those heads would be helpful.

Brad Hutchcraft

iTrader: (8)

More info on your combo as well. What springs are you running, valves, lifters, pushrods, and was the camshaft degreed?

SpinsB

iTrader: (5)

MTI (out of business) did the heads.

SSPerformance

iTrader: (76)

Problem is not in those heads.... almost like your down a cyl you need to do a leak down test

30th t/a

iTrader: (51)

Sell the heads and buy a set of tfs235s and a set of 1 7/8 lts, port the 90mm intake and get a custom cam. You should be over 500 easy.

Wnts2Go10O

iTrader: (12)

ill second the compression/leakdown test

then worry about buying new shiny things for it.

SpinsB

iTrader: (5)

all that info I have no clue. Long story short had this motor built years ago while still in college and didnt get any info from mti about details of internals. Let alone once I started to dig ion to what I had they closed up. yes i know how dumb but i was young and didnt know then what i know now. Im trying to figure it all out now.

ugh dont say that. Something like that wouldnt have shown up some how during my session.

GT-OH

iTrader: (7)

This!

Brad Hutchcraft

iTrader: (8)

Well, do you have any shots of the dyno graph?

itsslow98

iTrader: (18)

Sounds like a **** poor pile of parts that were thrown together. Thats the bottom line IMO.

Brad Hutchcraft

iTrader: (8)

Honestly, you said that it was done making it's power quickly.. that's where I'm curious.. If those heads have been used for a couple of years, and are the original springs from MTI, maybe the springs are worn out, causing you to float the valves? If you are going to run a compression check, why not do a check up on your valve springs to see where they're at? That shortblock sounds like a nice foundation, so if it checks out alright... I would recommend pulling the heads, and shipping them to a Vendor like TEA or AI.

Advanced Induction offers a rebuild service on cylinder heads for under 500 bucks that will have them working as new. As a bonus, if there is anything wrong with them, they can make the necessary repairs/replacements, restoring any lost performance.

I'd say its money well spent! Moreover, if you decide that you want to run a different cylinder head, having these gone through and brought back to prime condition will make it much easier to sell them, giving the next buyer a solid head to work with... It would make it a much easier sale.

The more info you can get on your build, the easier it is to trouble shoot, and diagnose any problems that might pop up. This is where it pays to be an informed buyer, you know? Good luck, keep us updated on any progress!

Brad Hutchcraft

iTrader: (8)

That shortblock sounds REALLY nice, actually. And the Cylinder Head is older, but may still be a performer! We don't know yet. He has nice parts, he just needs to invest some time and money into the little details. Those heads may need a few hours of work, but when finished, he may find 50 horsepower!

itsslow98

iTrader: (18)

FAST 90+ 1 3/4 long tubes+ a 3" ypipe are all less them optimal for a 427. If it were at least a ported FAST 90+ 1 7/8 headers+ 3" true duals id almost guarantee he'd reach his goal.

My guess on the reason is peaked early is the intake and exhaust couldnt keep up at higher rpms. ANd the above shows restrictions in the intake and exhaust. Clear those up and youll have a stout combo.

Also, speed density or maf tune? If a maf what size is it?

Brad Hutchcraft

iTrader: (8)

I dont think he is going to pick up 50 RWHP from a change in primaries and a port job on his FAST manifold. NO, those headers aren't enough for a 427, and he's leaving some on the table. And YES, porting that FAST manifold, or a switch to the 102, would help his combo make more power, but ONLY if the motor will spin that high... We haven't seen any information from his trip to the dyno. NO graphs, no idea on his tune, no real SPECIFIC details on his combo. So the best we can do at this point, is guess.

I agree he is leaving a considerable amount of power on the table with his 1 3/4 headers and untouched FAST 90, but I don't agree it's worth 50 RWHP....

SpinsB

iTrader: (5)

MAF tune 85mm graph to come. Thanks for all the input guys. More info to come