Chevy heads-what fits what?

On chevy heads--what is the year they went to the 2 bolt valve covers? Do the newer style heads (2 bolt) bolt up to the old style (4 bolt) compatable blocks? How do you identify vortec heads? Are all angle plug heads vortec heads? Are all alluminum heads vortec heads? Basically what fits what? Bill rinaldi

 

Chevy went to two bolt covers in 87, All SBC heads will bolt to a SBC block. But pre 87 intakes will not fit post 87 heads, the center four bolts are different angle. Vortec heads have only four bolts each side holding the intake on. Thus, only Vortec intakes fit these heads. No factory production angle or Vortec aluminum heads.

Aftermkt is very confusing to the novice. Virtually any combination available. Just match up the intakes to the heads.

 

Im not sure what you are talking about exactly with the 2 bolt design, the first generation, the one piece rear main seal engine and the now LS series engines all incorporate a 4 bolt valve cover. The center bolt valve cover engine started in i think as early as 86 they are the same format as the first generation but have a one piece rear main seal crankshaft and center bolt valve cover design , just because it has center bolt valve covers does not mean it is a vortec. The vortec engine was a feul injected engine and the other was a throttle body. Vortec engines came out in I think 96 and were replaced by the LS series

 

This isnt correct. 1987-95 (TBI) heads are the 4 centerbolt style. I dont recall if Vortec heads (started in the 96 model year) are 2 bolt, but I am pretty sure they are also 4 bolt.

 

There is no stock 2 bolt valve cover on a small chevy. Like Rocket said, everything up to the LS series can be made to work, everything pre 85 will bolt together. The valves may not clear, and the steam holes for a 400 may not be there, but they will bolt on. 88 and up blocks don't have the fuel pump push rod bored in them. Real Vortec require a different intake. Some (most) centerbolt heads have a different angle on the inner intake bolts. All of these can be overcome to make it work.

 

More often than not that's true but there seem to be exceptions. I have a '96 and a '97 block that are both fully machined for a mechanical fuel pump, push rod hole and all. I had an '89 block that was not. I have seen them with no machining at all and with the mounting pad machined but no push rod hole. There doesn't seem to be any rhyme or reason to it.

 

Sorry----I meant 4 bolt center mount valve covers. So if a 76 350 engine gets the later style heads (post 1986- non vortec) put on it, the Edelbrock manifold used on the 76 will not fit, it needs a newer style intake to work. OK, are the angle plug heads vortec heads? BILL RINALDI

 

No. You can I.D. a Vortec by its heart-shaped combustion chamber and casting numbers ending in "062" or "906" only. There are NO other Vortec heads.

 

I replied to the "two bolt" covers just explain the differences between side bolts and center bolts. He knew what he meant and I knew what he meant..We all know there are exceptions to the rule on SBC production head and block changes. On some vehicles the side bolt cover heads were continued for a time after 87. HD Vans, HDTrucks, Industrial etc.

I see so many guys that think their high rail center bolt heads are "Vortec"