Will A Intake Manifold For a Ponitac 1960's Big Block 400ci-455ci With Fit On A Buick Big Block 430?

Question

Does Anyone Know If An Intake Manifold For a 1960's Ponitac Big Block 400ci-455ci With Fit On A Buick Big Block 430ci? I Know That All Parts Are Inter-Changable On The Buick 400ci-455ci Engines Alone, But I Am Not Sure If Buick And Ponitiac Big Blokck Parts Are Interchangable. Please Only Answer If You Really Do Know Because I Really Don't Want To Phu*k Up My Engine. Thanks

Answer 1

Nope, no parts are interchangable between Pontiac and Buick engine families.

Pontiac does not use the "big block" "small block" naming system. All the pontiac engines are the same external size, from 326-455. Pontiac uses "small journal" and "large journal" to describe the differances between engines. 400-smaller engines used the same basic crank dimensions on a 3" main journal. 421-455 used a 3.25" main journal. Most parts will interchange between Pontiac engines built between '67-78, but will not fit a Buick.

Pontiac engines by year and crank size:

389 '59-'66 3" mains, 3.75 stroke
326 '64-'68 3" mains, 3.75 stroke
350 '69-late 70s 3" mains, 3.75 stroke
400 '67-78 3" mains, 3.75 stroke

421 early 60s-'66 3.25" mains, 4" stroke
428 67-69, 3.25" mains, 4" stroke
455 70-76, 3.25" mains, 4.21" stroke

Its a common mistake to think that all GM engine parts will interchange. Before '80, GM divisions all had totally different engine designs. Poncho and Buick were two of them. Even tho they are both 455s, they are totally different internally.

Answer 2

Why even do it??? It would take alot of work for a bad engine. The 351M-400 is one of the worst V-8's Ford ever made. They might of been alright for Gramp's Country Squire, but for a performance engine, there are much better choices. Use a 460 if you want big block power, or use a stroked 302 for a simplistic swap.

Answer 3

no it won't , the transmissions may interchange 'though