bigchief

I tried to replicate how much heads would change my cars performance with desktop dyno, right now i'm running 305 TPI heads on my 355, and i would like to put these heads on it:

HEADS

Do these Desktop Dyno Results look realistic???

Orr89RocZ

iTrader: (20)

with stock TPI on there with those heads? 376hp will not be made at 5500 rpms it will peak in the 4500 range and probly make 330 ish hp on motor with stock TPI and full accessories. With upgraded TPI that flows more, you could see 350hp or close to it i bet

thats not too bad, should be close to 300 whp. Full bolt on L98 is around 240 with stock TPI and 255-260 capable with good intake setup. cam and heads are probly worth near 40 whp.


Piece of advise tho.. TPIS port job is good but price is alittle high i think. Consider talkin to lloyd elliot over at eportworks.com. He probly could do the same job and get more flow for couple hundred less

then consider your only 200-300 bucks away from good aftermarket setup that will flow more like AFR 180's

85irocz355tpi

Wow I'm running a tpi 355 with 305 heads. I have a slightly bigger cam though. I guess those heads are pretty good. My desktop dyno only puts mine at 310Hp on the flywheel. Stock tpi with headers true duals, hypertech chip, screenless maf, modified air box with k&n's, and some mild head work and tpis fuel pressure regulator. I'm gonna put it on a chassis dyno in about a month to tune in the fuel pressure regulator and we'll see how close desktop dyno is.

1989GTATransAm

iTrader: (3)

You can deduct 5% from those horsepower numbers right off the bat. Those numbers are on an engine dyno with no accessories. I bet those flow numbers are a little optimistic.

Orr89RocZ

iTrader: (20)

lloyd elliot quoted me around 260 cfm from a L98 head. they got less material to port than LT1 versions and Iron L98 heads. So they can get them in the 180cc range i believe but only can squeeze 250-260 out of which aint bad at all... thats more than enough for most street car setups

1989GTATransAm

iTrader: (3)

That is in the same range as the Trickflows we have had flowed.

bigchief

so basically you guys wouldn't suggest i spend the money on porting my heads, instead i should spend 1200 on something else? what flows better for 1200?

1989GTATransAm

iTrader: (3)

Not at all. Is the $1250 price with you giving them a #113 head as a core. If you do not have a #113 core is $700 added to the $1250 price?

Orr89RocZ

iTrader: (20)

i'm not sure how it works but i think you pay a core charge. So to avoid that you ahve to buy a set of 113 heads for 300-500 bucks these days and thats 1500-1700 for heads

i'd just get AFR 195's at that point

1989GTATransAm

iTrader: (3)

Hehehe. You are reading my mind. Another head to give carefull consideration to is the new Dart Pro One Platinum series head. Suppose to be pretty good according to the engine builders.

bigchief

i have the heads in my garage, i got them for free on a 355 block that some guy took out of a vette b/c it wasn't the stock block, and he wanted the car to be 100% original. the heads also came with comp 1.6 roller rockers. so no, i would not have to pay the core charge, but who knows how much shipping would cost........

Orr89RocZ

iTrader: (20)

i'd say 45-50 shipped. My iron L98 heads cost me about 70-75, depending on location tho and now if they charge more for a fuel surcharge or something