[NHRASuperStock455SD]

Will someone please post a picture of the motor mount locations on the frame, hopefully 75 & up? Not the clam shells. I could also use 1970 pictures.

[Scarebird]

Missing something here - the clamshells are the part that do mount to the frame... and did you want Chevy or Pontiac/Olds mounts?

[gillyiowa]

you are referring to the lower mount that bolts to the frame, right?. I have a pic somewhere of the right holes to bolt to according to what engine you have if this is what you need. I just have to find it

[74Grandville]

I know on my 79 the pontiac mounts can only go in one location even though there are a bunch of holes.

[gillyiowa]

This what you need?

[NHRASuperStock455SD]

Perfect Gilly! Can you please tell me what year that is? Here is the old firebird frame we built for a header/exhaust manifold fixture. I am trying to verify the correct bolt holes on the frame to use. We put the clam shells, new motor mounts, and the bolt holes dont line up!

[gillyiowa]

These are from a 78. 77-81 are the same. I ran into the very same thing, PITA. I bolt the clamshell to the frame mount,lower, use a small punch to line them up, insert lower mount to frame bolts, then squeeze my fat hands in through the lower frame to get the nuts started. Leave all bolts/nuts loose until you get the nuts on the bolts then go to town. I have more pics somewhere, have to figure out where.

[dmorg1]

This is a 79





Dave

[NHRASuperStock455SD]

Thanks so much, I would appreciate any additional years people might have. We are duplicating tubular RAV exhaust manifolds to fit as many applications as possible to match the ones attached (upgraded performance). Does anyone have a picture of any 1970-1974?

[Craig Hendrickson]

Lynn,

Are those pictures of original Pontiac exh manifolds or your repop?

Craig

[NHRASuperStock455SD]

Originally Posted by Craig Hendrickson

Lynn,

Are those pictures of original Pontiac exh manifolds or your repop?

Craig

Hi Craig,

yes

[NHRASuperStock455SD]

Craig,

Sorry misread, these are the factory ones, mine are tubular with much bigger 2 inch primaries & 3 or 3 1/2 inch Vband.

[Skip Fix]

Lynn I think I even have an 81 assembly manual that shows with holes for what GM motor

[Grand73Am]

Originally Posted by NHRASuperStock455SD

Perfect Gilly! Can you please tell me what year that is? Here is the old firebird frame we built for a header/exhaust manifold fixture. I am trying to verify the correct bolt holes on the frame to use. We put the clam shells, new motor mounts, and the bolt holes dont line up!

The clam shells are the motor mounts. Then there's the engine mounting brackets that bolt to the engine. If you don't have engine mounting brackets that came from off a Pontiac engine from a 75-81 firebird/TA, they won't fit in an f-body. No other brackets will work. So, if the engine brackets came from an engine from another model of Pontiac, that's another possibility for them not fitting.

[Ben M.]

Originally Posted by Grand73Am

So, if the engine brackets came from an engine from another model of Pontiac, that's another possibility for them not fitting.

Amusingly, you'll find that many people will sell the '77-81 B-body or '78-81 G-body 265\301\400 mounts as F-body mounts. They truly will not work (and are a good 3/4" wider on the passenger side).

[Scarebird]

Originally Posted by Ben M.

Amusingly, you'll find that many people will sell the '77-81 B-body or '78-81 G-body 265\301\400 mounts as F-body mounts. They truly will not work (and are a good 3/4" wider on the passenger side).

I have a set of those - wonder if they are worth replicating?

[Grand73Am]

I think someone should reproduce the pontiac f-body engine brackets. I think there's a good demand for them with people wanting to swap Pontiac engines into firebirds/TA's that originally came with Olds or Chevy engines. The correct used ones occasionally show up on eBay for around $100 a pair.

[NHRASuperStock455SD]

I got the GP clam shells, & they didnt work. These are for a Firebird according to the GM part numbers. Are the GII Firebird 301 clamshells different from the GII 400?

[Grand73Am]

Yes, the firebird/TA 301 clamshell motor mounts are the same as the clamshell 400 motor mounts.

Question is whether you have the correct firebird/TA engine brackets? The part numbers that should be on the brackets are 496892 and 496893.

[Ben M.]

Originally Posted by Scarebird

I have a set of those - wonder if they are worth replicating?

Sure are.

And the clamshell mounts for 1975 and later Firebirds are all the same, it just depends on where you put the holes to line it up for which engine (Chevy is different than Pontiac). The block mounts are what are different really. 301 and 400 Pontiac engines all use the same block mounts, but ONLY for an F-body will they work. B\G are a no-go.

The picture below is of B-body mounts on an engine. They are noticeably wider and lower than for the F-body: