On D Port Crate motors, what would be the recommended exhaust manifold configuration or part number/s. Is this a critical issue? With no doubt, I need some serious help in this area. Thanks, Dennis - I have to assume this must, in some way, be a Corvette realated question... DC
-
-
Re: Crate Motor D Port Exh Config... Help
Dennis,
Are you refering to cylinder head part no. 14011076? According to my Chevrolet Power book seventh edition, 1994 says head is also considered to have standard port locations and also referred to as a "C-port" head. If that is applicable, cast iron manifolds of the Gen IV variety would bolt right up to it. 1973 & '74 right hand is part #3880828 & left hand is part #3969869. '71 rgt=3990828 lft=388089 or 3969869 '72 rgt=3880828 lft=3969869 '70 same part nos. as '72 1969 rgt=3880828 lft=3880827, 1968 same nos. as '69. For mid years you will have to have another person with the appropriate Corvette Specifications Guide by John Amgwert reply.
Happy Corvetting, David Nims member #19639 save the wave~~~~~~~~~~~~~~~~ -
Re: Crate Motor D Port Exh Config... Help
Dennis------
I'm assuming that you're talking about the "D"-port aluminum heads used on the ZZ-series small block crate motors and as also used on 87-91 Corvettes. These heads have the ports 0.100" higher than most other Chevrolet heads.
For the most part, I think that you can use the stock-type cast iron manifolds as-is. However, for lowest restriction, the manifolds can be more-or-less "port matched" by relatively minor grinding. For stock-type manifolds, I'd go with the 62-65 Corvette 2-1/2" outlet manifolds which are still available from GM under GM #3797901, 3814970, and 3846563.
Another option would be to use the 87-91 Corvette tubular manifolds. These will bolt right up and match the ports perfectly. However, they will have extra "pipes, tubes, and fittings" attached for the 87-91 emissions control components. The manifolds are still available from GM under GM #14087511, left side, and GM #10055734, right side. That's the good news. The bad news is that they currently GM list for $616.97/each.
Also, I THINK that the 92-96 LT1 cast iron manifolds will fit these heads. Once again, there will be extra "fittings", but no extra tubes. Just one part number fits either side and it's GM #12554232. It GM lists for $178.57/each.In Appreciation of John HinckleyComment
-
Re: Crate Motor D Port Exh Config... Help
Dennis I used my original 70 cast iron exhaust manifolds on my D Port Crate motor with aluminum heads. It is of course not a perfect match, and I don't know of any dyno runs of comparison of type of other exhaust manifolds.I think it performs very well. I installed the Corvette type valve covers on my engine instead of using the steel ones that came on the crate motor. My 70's exhaust manifolds were slightly modified because of a interferance fit against the valve covers, just a little massaging was necessary from the contact area. My 70's manifolds never leaked on the original engine, however there was a very slight exhaust leak when installed on the aluminum heads. I installed C4 exhaust manifold gaskets and sealed it up.Comment
-
Thanks all for the guidance... *NM*
Comment
Comment