dredre08

iTrader: (2)

Ok a few weeks ago I bought a 88 Iroc with a 350 TPI, beside it needing a donut gasket it seems to run fine. Well the other day out of sheer curiosity I popped the oil cap off the head cover and looked at the head casting numbers, well to my surprise these werent TPI heads, they were 187 casting tbi heads(swirlies), im assuming that the heads are completely stock with no work done to them. There is a guy on this site who is selling a set of 081 TPI heads with a couple extras put into the heads. He says that they have the following upgrades:

- 1.94/1.55 Valves
- Machined Valve Guides with springs for .525" lift
- slight bowel port work
- Pressed in studs removed for screw in units with guideplates

Well i have a little extra cash after the holidays from my parents and what not and I was wondering would I see a significant gain by swaping the 187 heads for these 081 TPI heads?... I ask because alot of people on the site say that the swirl port heads take away from the performance of the tpi but I have also read that swapping a stock head for another stock head will probably not be much of a gain.

I know you guys are going to say just get some aftermarket heads but I dont really have money for aftermarket heads as I am a College student living on my own and i believe the heads that he is selling are ready to bolt on so thats right in my range lol.....

PLEASE HELP GUYS, I need input asap because the guy should be getting back to me with the shipping quote soon.......

dredre08

iTrader: (2)

Anybody?????

TTOP350

iTrader: (8)

Its worth it.

dredre08

iTrader: (2)

Do you think it will be a noticable gain?....

dredre08

iTrader: (2)

anybody else got any input

1MeanZ

iTrader: (9)

if you're pulling the heads, I wouldn't put stock 081s back on unless they were heavily ported by an experienced porter with flow bench data to back it up. I'd be looking for over 250cfm on the intake side at .500 lift as a benchmark, and to use that you'll need to fully port your stock intake parts at a minimum. Stock for stock I don't think you'll pick up enough to make it worth while. I put swirl port 305 heads on a TPI 305 I built a few years ago and it ran great. With a stock cam, stock intake, and especially stock exhaust I really don't think it will be worth it.

Damon

If it's actually a 350 (I'd check since it's obvious you have a "frankenstein" motor with at least mismatched heads) those little 305-sized 187 swirlies are choking it pretty bad. The correct TPI heads for a 350 would be -083 castings. Worked -081s would probably be about equivalent to them flow-wise, maybe even a bit better depending on how good the bowl and seat work is.

You have any idea the specs on that motor besides the heads? Would be nice to know what kind of cranking compression you have as well.

305-sized heads are great for building compression on a dished-piston 350 bottom end to get compression up into the mid 9s. But if the bottom end of that "350" already has flattop pistons you could be looking at almost 11:1 compression- too high.

1MeanZ

iTrader: (9)

You're right I missed this. The 187s will be bad news on most 350s unless it's got dished pistons or something. Pull the casting number off the bellhousing pad behind the driver side cylinder head and see what you have. it might just be an L03 dumped in there...

TTOP350

iTrader: (8)

I guess I should have said its worth it to ditch the TBI heads...

dredre08

iTrader: (2)

Im going to check that first thing tom...... I was thinking the same thing when I seen the heads, the guy told me that it was not the original motor but he said it was a 350, and it seemed to have a noticeable amount more power then my old 305tpi that I had in my old trans am... I hope i didn't get burned!!

dredre08

iTrader: (2)

matter fact im about to go check now!!!, is removing the bellhousing hard to do??

1MeanZ

iTrader: (9)

LOL you don't have to remove anything, just look at the flat pad behind the driver side head. IT is hard to see in the car but its the only way you'll know what you have.

dredre08

iTrader: (2)

Is it by the alternator??

1MeanZ

iTrader: (9)

no. back of the engine by the firewall

TTOP350

iTrader: (8)

No its the rear driver side. by the brake booster/ firewall area.

dredre08

iTrader: (2)

lol im probably going to have to let someone else who is a little bit more knowledgeable about engines, Im looking where you guys are telling me to but its impossible to see through all these wires or im just looking in the wrong spot.......

abray1

If your going to spend a few hundred bucks throw in a couple hundred more and at least vortec or aluminum vett heads. Stock parts deliver stock performance.

BuzzLOL

.. Below distributor on bellhousing on driver's side... use a flashlight... or possibly on passenger side in front of head...

.. I wouldn't change the heads... keep your money and get through college... the current cam prolly isn't taxing the 187 heads...