Heat riser and exhaust manifold gaskets for an '88 454?

[atikovi]

[size=78%]Would anybody know the brand and part numbers for the exhaust manifold gasket, exhaust pipe seal and heat riser gasket? The manifold is stainless steel, not cast iron and has round ports not oval.[/size]





I think the manifold takes a Fel Pro 1412 or Mahle 95100SG and the exhaust pipe a GM 15592451 or Fel Pro 60584



That leaves the heat riser gasket and after a day online I haven't found anything specific. The distance between bolts is 3 9/32" and the hole diameter is 2 9/16" but I cam up empty.  Any suggestions?

[/size][size=78%]

[Rickf1985]

https://www.classicindustries.com/product/tf700542.html


https://www.google.com/search?rlz=1C1PRFE_enUS666US695&sxsrf=ALeKk00vhp_HPCdiuqVw7pLQoJo83b-otQ:1589674982086&source=univ&tbm=isch&q=1988+Chevrolet+454+heat+riser&sa=X&ved=2ahUKEwjF-_Xk0LnpAhXPhHIEHZLUBIQQsAR6BAgDEAE&biw=1920&bih=969

[atikovi]

Thanks but that only shows as fitting up to 1972. Wonder if it would work for a newer model.

[tarifachris]

[size=78%]Would anybody know the brand and part numbers for the exhaust manifold gasket, exhaust pipe seal and heat riser gasket? The manifold is stainless steel, not cast iron and has round ports not oval.[/size]

[size=78%]
You blocked the air system from outside... My tip is remove the inside tubes and your exhaust manifold will have 30% better flow! For the heat riser I used no gasket and put high temp gasket maker on - to be honest there was no gasket before. Replace both donuts - I replaced one and one year later the other side broke in pieces.
[/size]

[tarifachris]

Did your manifold leak before? These SS manifolds were better than the iron ones but they can leak and deform as well. Check if they are 100% level and I would use these gaskets for the exhaust manifold...https://www.holley.com/products/discontinued_product/parts/29D04BERL
Lol, just realized they are not available anymore... To bad, but I am sure they are available somewhere.

[Rickf1985]

I used standard header gaskets on mine but as mentioned these do warp and they warp bad. Once they warp they also burn out a groove so they need to be welded in and refinished. I don't even remember what I used as the top gasket on my heat riser but that gasket should be the same. The reason it says to 72 is because I looked further back in the pick up trucks for it. They were all the same. I tried to reseal my manifolds several times, I even cut the flanges so they would seal independently and not warp but they still leaked halfway through the year so I am putting headers on and be done with it. Long tube headers will give better low end torque also. I plan to tie the headers into a 2 1/2 inch Y pipe into a 3" single exhaust out the side in front of the drivers side rear wheels.

[atikovi]

Did your manifold leak before? These SS manifolds were better than the iron ones but they can leak and deform as well. Check if they are 100% level and I would use these gaskets for the exhaust manifold...https://www.holley.com/products/discontinued_product/parts/29D04BERL
Lol, just realized they are not available anymore... To bad, but I am sure they are available somewhere.

Mine have the round ports anyway.

[tarifachris]

Mine have the round ports anyway.

They are all D shaped exhaust ports. Only the intake ports are different...

[atikovi]

They are all D shaped exhaust ports. Only the intake ports are different...

No, my exhaust manifold has round ports and I assume will take this gasket.

[tarifachris]

All exhaust ports from peanut port heads 236 look like this:These are my SS manifolds:These are yours:
Looks like your old gasket was not round.

[atikovi]

I'll take a picture tomorrow but my manifold ports are round.

[atikovi]

[Rickf1985]

He has round ports, and quite small ones at that! Could you possibly get a picture of the head exhaust ports. I am really curious to see what they look like. I remember that I gasket port matched the manifolds but I am pretty sure they were not round to begin with. Looking at yours the port matching has got to be terrible if you have the standard rectangular heads. Just the transition inside from the flange to the pipe is dismal. The factory just did not care at this point.


Here is a better pic of the old high performance oval port heads.


https://www.ebay.com/i/254450570001?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=254450570001&targetid=885787207871&device=c&mktype=pla&googleloc=9003783&poi=&campaignid=6469750693&mkgroupid=89345420792&rlsatarget=aud-622524042958:pla-885787207871&abcId=1141176&merchantid=6296724&gclid=CjwKCAjw5Ij2BRBdEiwA0Frc9UagqK5sqscR2FtOQe8uu3hO1w93cqsQeGMYlF-kw3OO5YMW7BydkhoCn7sQAvD_BwE


And here is an even better shot, notice that the intakes are rectangular instead of oval and they are HUGE! So a stock intake will not fit.


https://www.ebay.com/itm/69-CORVETTE-CAMARO-BIG-BLOCK-CHEVY-396-427-SQUARE-PORT-HEADS-3919840-REBUILT/193343455603?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D225074%26meid%3D9772c9fb91b14e9d9426aa4ba5410cc1%26pid%3D100677%26rk%3D2%26rkt%3D30%26mehot%3Dnone%26sd%3D254450570001%26itm%3D193343455603%26pmt%3D1%26noa%3D0%26pg%3D2386202%26algv%3DSimplAMLv5PairwiseWeb&_trksid=p2386202.c100677.m4598

[atikovi]

[Rickf1985]

Well, at this point I am at a loss as to what you have as far as manifold and heads. I have been out of the shop for quite a while now but I was not aware that they brought back the oval port head. I am positive that it is not the closed chamber head or you would have to be running avgas in it to keep it from pinging at 12:1 compression. And I have never seen a Chevy exhaust manifold with round ports. So short of checking serial numbers I don't know what to offer. Those heads look to be original to that motor and that motor mount appears to be the original one so from what I am looking at I would say that is the stock engine for that year of the vehicle. Order a set of exhaust manifold gaskets for that year 454 truck engine. As far as the heat riser if it is a machined metal to metal fit then go with the red, high heat silicone gasket maker. That is what we used on air cooled aircraft exhaust manifolds.

[atikovi]

I got the gasket 1412 as shown in reply #8 from Fel Pro, used a Walker 31589 that I had to trim slightly for the heat riser and got a Fel Pro exhaust pipe donut. Runs quiet now.






Next job, idler arm bushings.