FocusGhia

The car is smoking on startup and using a bit of coolant.
I'm assuming it's the head gaskets.

So I'm getting them replaced in January which I figure gives me time to order (cos I'm in the UK) a couple of bits and pieces to drop in at the same time.

What's worth doing at the same time???

I can't afford to buy new heads by the time I've added shipping and I can't go to a breakers yard and pull bits off a corvette, this is the UK and these cars don't hardly exist over here!

Cam or rockers perhaps? They're fairly light to ship.


The car is an 88 305 TPI Auto with 2.72 posi rear end
mods: Transo shift kit with Corvette servo, Performance Resource PROM, ported plenum, descreen maf, high flow air filters, tb airfoil, fuel pressure bumped to 47psi.

I'm planning on changing the rear end gears to 3.43 posi


Suggestions?

1MeanZ

iTrader: (9)

lots of folks on here have had excellent results porting their stock head castings. do a search for some posts by sitting bull, i think he has had fantastic results with stock heads. so order a head porting kit from summit for $40 and go to town. the smoke on startup is not head gaskets, it is worn valve seals which are an easy fix as long as the valve guides arent worn out too bad. your machine shop can resurface the heads and recut the valve seats once your porting is done.

also since you have the 305 TPI with the 2.73 rear, you may have the peanut cam. a cam swap could help you a lot, and some roller rockers wouldnt hurt either.

many guys on here with ported stock iron heads, better cam, headers, and a decent rear gear (3.23 or better) are running 13s in the 1/4 mile.

FocusGhia

What cam should I go for?

I thought the 88's had roller cams in them?


So if I get the heads ported and the rockers and cam replaced which should I buy?

I'll go for 3.43 gearing.

Also, should I switch to a different stall converter?

FocusGhia

Anyone?


Also, I could fit some Corvette aluminium heads.
In which case which cam should I go for then and should I be changing the runners and base if I have those heads?

1MeanZ

iTrader: (9)

the topic of cam selecion has come up a million times on here just do a search. my cam specs are listed in my sig and i have stock intake runners and base and i am running the aluminum heads.

speed88

If you go to the Comp Cam website you can look in there online catalogue and they have a number of cams that are for TPI'ed motors. They list what cam is best for what application, such as stall or aftermarket chip etc. Try there. Or try a search on these boards.

89Warbird

If you have the heads off put on headers, always a good investment and easy to do with the heads off. I also agree with a pocket port and new cam.

FocusGhia

Thanks Warbird and Speed88.

i'll take a look at the Comp Cams website and ensure I get the headers done at the same time (they were planned anyways) to save a few $$$.

1MeanZ, I DID do a search (as always) if I had found a definitive answer I wouldn't be asking the question. Oh and your sig ain't showing on that post.

Damon

2 things I never miss a chance to do to a stock head if I happen to have it off the engine anyway.....

1. New valve guide seals. If you get little oil smoke puffs on startup and when hitting the gas quick this is probably why.

2. Upgrade the valve springs. Even if you're using a stock cam chances are you springs are worn out originals anyway. If you're using a more performance oriented cam then dropping in some Crane 99848 springs in place of the stock units can be done very easily without machine work. They're true bolt-ins and are significantly stiffer than stock and will control a mild performance cam MUCH better at higher RPMs. If you have a more serious cam then there's absolutely no substitue for putting in the recommended springs, even if it requires machine work.

I also like to have the guides machined down by about .100". Haven't met a stock GM head yet that couldn't stand to have the retainer-to-guide clearance opened up to be safe. Most stock heads have interference around .470" valve lift. My machining down the guides by .100 you are safe up to levels you'll never actually lift the valve unless you're nuts (.570"+)

FocusGhia

Damon, that was EXACTLY the info I was after.
Thanks very much for taking the time to reply.

I am getting smoke on startup hence the heads are getting the valve guides replaced.
I'm also getitng some coolant loss which I am hoping is down to the head gasket (no visible smoke on acceleration so it can't be too serious).

I will buy the springs and give them to the shop to use when they rebuild.

I'll also enquire with them as to the cost of getting the machining done.

Thanks again!