[notmrgoodwrench]

ok i have a 400 sbc and was gonna put it in my truck the other night i went to bolt the exhaust manifolds on before i stuck it in and guess what they didnt fit the motor is a 70 to a 73 model and the manifold i have came off of a 305 sbc in an 81 silverado the passenger side manifold fir all except the last bolt hole didnt line up the manifold was a litle too long but the rest of the holes lined up perfectly on the side and on the drivers side the manifold covered up the dipstick hole but all the bolt holes lined up on that side so what is my problem here i have never ran across this i have the manifolds that came with the 400 but had to change the passenger head cause mine was cracked but the head was the same as my old one so will these manifolds work and why wont the others work hell i thought they were all the same but im a redneck tho thanks for the help

[Deuce]

About 1979 Chevrolet added the 7th bolt hole to the heads and moved their exhaust manifolds bolt pattern to match. The 1979 and up heads will accept pre 79 exhaust manifolds but the early heads will not accept the later manifolds.

Just find a pre 79 exhaust manifold that fits your combonation.......

[stcam427]

chevy made a steel plate that bolts to the number eight exhaust port and allows you to install the late model manifold to the head. mid eighties had quite a few of them on the road so finding a plate to fit yours shouldnt be a problem.

[notmrgoodwrench]

hey thanks guys i have the old manifolds that came on the 400 so ill use them they should work i guess in the past i stayed with the older stuff and thats why it all interchanged hell take it out of one and put it in another no prob. butthe newer you get the more complicated i guess but thanks again guys