[Robby D]

Is part number 474840 on an RA manifold the long branch or the "boxy" type RA manifolds?

Thanks

[Robby D]

Is part number 474840 on an RA manifold the long branch or the "boxy" type RA manifolds?

Thanks

['ol Pinion head]

Are you sure its a RA manifold & not std log manifold? A part # starting with a 4 implies '70 & later but not late '70's which start with a 5. Original Long branch manifolds would have started with a 97...

closest # is #478140 = '70 A -70 1/2 F RAIII LH manifold
(fit F & A-body chassis, but was redesigned from '69 style A-body RA3 manifold to clear Z-bar in 2nd Gen F-body chassis).

For reference, '67-69 F-body D-port longbranch manifolds

9779495 LH (same as 65-69 big car HO)
9779493 RH (has flapper)
9791607 RH (flapper? I believe so)
9797073 RH (no flapper)

[chas-3]

Are you sure that is a Pontiac manifold?
My sources show some additions to what ol' Pinion head found. The closest part numbers I find are as follows:

478141 1970 Ram Air IV left side Firebird and GTO
1971 455 HO left side

490142 1969, 1970 standard right side Firebird
490143 1969, 1970 standard left side Firebird

490802 1973, 1974 standard right side Firebird
490803 1973, 1974 standard left side Firebird

[Robby D]

Thanks Folks. To tell the truth, the info I posted was mistaken. It is an ad on eBay. Here is a copy/pate from the listing--RH side part #9799720, date code K069. LH side part #478140-1, date code #J239--

Shed any light? Sounds like a mismatched pair at least as far as the numbers are concerned.

Robby D

[Held for Ransom]

Sounds right to me. 1970 GTO/Firebird RA III exhaust manifolds, RH and LH. Those casting dates would probably indicate they were originally off a GTO.

[chas-3]

Nope, not a missmatch. Those are the correct numbers for a 1970 Ram Air III Firebird.

[Robby D]

Thanks for all the help. I get lots of it here, kudos to the members...

Now, do you guys think these manifolds would be OK on a 67 400 bird? Incorrect, yes, but will they fit ok? (any engine compartment problems- I know they will bolt on to the motor).

Robby D

[chas-3]

Robby,
First off you need to understand that I am a purist. My two Trans Ams ('69 & 1979 TA/TA) are bone stock and will remain that way. I go for originality all the way.

I would be somewhat hesitant to do that swap just due to the fact that the manifolds are off a 2nd generation Firebird with very different dimmensions than the 1st gen cars. I would try to locate a set of 1st gen. RA III manifolds. I don't know the name of the company but these folks are supposed to have repro and used 1st gen. RA manifolds: 810-750-1421.