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MG MGB GT V8 Factory Originals Technical - 215 intake manufold on a 300ci?

Will an intake manufold from a Olds 215 fit properly onto a 300cubic inch Buick block?
Dana

Dana,
I have an Offy 215 intake manifold bolted to Buick 300 heads, which are on a 215 block. The heads had to be milled to maintain 9.5:1 compression, so the intake runners had to be milled a little as well in order to allow the bolt holes to line up. You probably won't have that situation, so everything should line up as is. The manifold intake ports are a little smaller than the intake ports in the head, so you may want to do some minor port matching on the intake and gasket, but it doesn't look too drastic. I didn't bother at the time, and will have to see how it runs before I think about going back to do that.

Best, Joe
Joe Ullman

I should have qualified what I said by noting the fact that I don't know if the heads lay on a 215 block in exactly the same position as they do on the 300 block. I 'think' the blocks are the same size, but before investing money take that into consideration. Sorry, I guess I didn't help any at all. Joe
Joe Ullman

Thanks Joe. It is not about investing money rather, wondering if the intake manufold on my failed MGB V8 conversion would fit on the 1966 Buick Special my son recently aquired with a 2 barrel carb.
Dana
Dana

I always thought the the 300 block had a wider 'V' because it was taller then the 215. If I am correct then the 215 manifold wouldn't be wide enough, the decks could be machined and thinner head gaskets may be available. The squish clearance could be tightened up at the same time. I'd do some more research or fit something from a 300. A 300 manifold will have the larger runners needed to match the 300 heads. Mike.
m johnson

The Buick 300 block is about 1/2 inch taller than a Buick 215 block (9.5" deck height versus
8.96") so the Buick 300 intake is wider. To use a Buick 215 intake on a 300 block, you'd
need spacer plates. In 1964 (and maybe '65), Buick made an aluminum dual plane intake for
both 2 barrel and 4 barrel carbs. Later intakes were cast iron. The early Buick intakes are the
only aluminum intakes available for that motor. No aftermarket intakes were made. It's a
fairly decent intake with ports larger than a 215 and the ports are identical between the 2
barrel and 4 barrel engines. The 4 barrel versions are fairly rare but you could modify a 2 barrel
with a bit of work. The only 215 intake I know of with 300 sized ports is the Huffaker single plane.

Dan Jones
Dan Jones

The 300 Buick block will not take a 215 intake. The 300 intake is it's own valley pan, & the 215 valley pan will not fit the 300 block. Dimensions are considerably different.

That said, with enough time & money, anything may be possible.

Anyone out there with a spare 300 4bbl intake they would like to sell, please contact me off list.
Jim Stuart

I wondered if Buick 300 alloy heads would fit on earlier 215/Rover V8. Somebody knows this?

Frank
Frank

Yes, the aluminum 1964 Buick 300 heads will bolt on a 215. You will get larger valves, and a larger combustion chamber, resulting in a much lower compression ratio, & an "overhang" from the miss- match of the 215 cylinder bore & the larger diameter of the 300 combustion chamber.

As far as I can tell, the net result is lower performance.

If you were to bore the engine to something close to the Buick 300 cylinder size, add a 300 stroker crank, then the heads would make sense. Look to spend SERIOUS money.
Jim Stuart

What Jim says is, of course, true. That's why my 215 block is bored to accept Chevy 305 pistons, and the 300 heads are milled to give a proper compression ratio. It's a real hybrid, designed by someone who knows what they're doing (not me, I'm just the wrench). We used big Olds diesel valves, and the pushrods come from Ford; the engine displaces right at 4 liters. It 'should' run pretty strong.

Joe
Joe Ullman

> Yes, the aluminum 1964 Buick 300 heads will bolt on a 215. You will get
> larger valves, and a larger combustion chamber, resulting in a much lower
> compression ratio, & an "overhang" from the miss- match of the 215
> cylinder bore & the larger diameter of the 300 combustion chamber.

The aluminum Buick 300 head has larger intake valves (1.625" diameter
versus 1.5" for the Buick 215) but the exhaust is the same at 1.3125"
diameter, though the Buick 300 ports (intake and exhaust) are noticeably
larger. There is room on the stock valve seats for larger intake and
exhaust valves, however. Combustion chambers are 54 cc's nominally versus
37 cc's for the Buick 215. While not ideal, the overhang is similar to
say a 350 Chevy smog head and doesn't seem to be a problem in practice.
There are fair number of 266 cube 215 strokers out there with Buick 300
heads.

> As far as I can tell, the net result is lower performance.

On a stock stroke and/or compression 215 this is very true. A good
bowl porting and valve job on the 215 heads would be more beneficial.
Flat top pistons (like the Olds 215 used) and a bit of milling (head
and/or block) will restore much of the lost compression but, to my
way of thinking, stroking the 215 is the best way to restore the lost
compression. You can also weld up the combustion chambers, if desired.

> If you were to bore the engine to something close to the Buick 300
> cylinder size, add a 300 stroker crank, then the heads would make
> sense. Look to spend SERIOUS money.

If you are rebuilding a 215 and looking at purchasing new pistons and
having the crank turned, the additional cost of stroking isn't that
much and you'll have a better selection of pistons (cast, hyper, and
forged). In that case, the Buick 300's larger ports and chambers come
in handy. The larger chambers keep the compression ratios in the right
ballpark.

Interestingly, the Huffaker Rover V8 single plane intake has ports sized
for aluminum Buick 300 heads. I've often wondered if Huffaker used
Buick 300 heads on his race motors instead of Rover V8 parts.

Dan Jones


Dan Jones

It sounds like the best way to get serious performance is use a 3.9 block (larger bore), go for the 300 head and new pistons + perhaps stroke further to say 4.2 or 4.4 liter.

Frank
Frank de Groot

>It sounds like the best way to get serious performance is use a 3.9L
>block (larger bore), go for the 300 head and new pistons + perhaps stroke
>further to say 4.2 or 4.4 liter.

Yes. Buick 300 crank and heads, Rover or Buick 215 rods, Rover 3.9L
block (also Rover 4.0L, 4.2L, 4.6L blocks) will yield 289 to 292 cubes
(4.7+ liters). There are even off-the-shelf pistons that can be used
for this combination from a 255 Ford V8.

I just happen to have all the parts for one of those...

Dan Jones
Dan Jones

This thread was discussed between 17/05/2002 and 23/05/2002

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