A buddy of mine just gave me a running 305 but the intake manifold has seen better days. I have an edelbrock performer for my 87 350 with a cracked block. The 305 is an 86 or 87 and is externally balaced like my 350. Will my post 86 350 intake bolt to this 305 or do I need to do some grinding? And if I do need to do some grinding how do I grind off. Thanks.

Yes the intake is the same. I have the same deal, First Gen SBC are the same.You say post 86, the vortec probably not.

not exactly it depends on if its an 86 or 87, 86 used the older style intake 87 and up use a different one when they went to a 1 piece rear main seal the only diffrence is the 4 center bolt holes go in straight not at an angle like the previous year. you can elongate the holes to make it work. the vortecs came out in later year truck like 94 or something.totally different intake.

It'll depend on the heads that are on the 305. If your '87 350 heads are original, the 4 center bolts are drilled at a 72* angle into the heads instead of a 90* angle like the older heads (pre-1987).

If the intake you have has the newer bolt angles, and the heads on the 305 are pre-1987 then you may have to modify the holes on the intake manifold in order for it to work properly.

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350CID, Vortec 062 heads, Magnum 280, Performer Intake, Holley 650 DP, 3.42 rear w/ Auburn posi, 2600 Stall/TC
"Things are more like they are now than they ever were before."
Former U.S. President Dwight D. Eisenhower

the 4 center holes will need to be modified on the intake... if you have a drill press and a vise thats best if not a hand held drill will work... they(the 4 center holes) have to be oblonged

take a look on ebay and you can see the diffrence