Big Block Ex-man Casting #s

[hotrodmtodd]

Does anybody have the casting #s for original exhaust manifolds for our trucks? Mine is a '71 GMC, Special Camper, 402/manual trans. It has headers now, but I am converting it back to manual trans, so it looks like I am going to have to go back to manifolds because I really don't want to smash the header in that far for the bellcrank. I have a set now, but I'm not sure what they fit. The #s on them are GM4 3864504 RH and 3832804 LH GM3 (I think) I need to know if what I have and what I need will interchange. Thanks, Mike

[hotrodmtodd]

ttt

[COBRO]

I checked the stock manifolds that came off my 72 402 with the 4spd. and they are not the same as yours. Mine are B99445 LH and 388310 RH. As long as they fit the chassie would think its just a matter of getting the head pipe to match and any exhaust shop can handle that. All BBC manifolds Ive seen are a standard log type with a rear dump - on mine the Pass.side dumps at about a 45deg.from the C/L of the log and the driver side dumps straight down at 90deg. HTH:::::CB

[COBRO]

After thinking on this for another minute (still early on the left coast) thats why the driver side dumps straight down so that it will clear the bell crank for the clutch assy. :::CB

[hotrodmtodd]

Cobro,
Thanks for the info. Is your truck 2WD? What headers did you use? Would you be interested in selling those manifolds if I cant get these to work? I am trying to cover all the bases. Let me know, Mike

[COBRO]

Mines a 2WD and came with the SM465 4spd - all that came out and I put in a th-400 trans.behind a 454. I used Hedman elites and they fit prefect and am very pleased with them. Something else you may want to look at is if you use they clutch assy. out of a mid 70s PU your headers should clear everything - at least thats the info that came with my headers - the bell crank mounts in a different location for the clearance. Just a thought if you would rather keep the headers on. Not sure on selling the manifolds - let me think about that one.::::::CB

[hotrodmtodd]

Yeah, the late model bellcrank mounts to the bell housing. Drilling holes for the frame bracket would be fun with the cab on. Plus you have to cut a different hole for the rod in the floor. I am either going to go with manifolds or bite the bullet and smash that #7 tube. I would also be interested in buying your old bellcrank & engine bracket reasonable if you still have it. I am doing this to my '69 Dumptruck as well. (BB) Let me know, and thanks again, Mike

[hotrodmtodd]

Cobro,
Just checking to see if you thought about those parts yet? Send me a PM if you can. Thanks, Mike

[Ironhorse]

Hey Mike, Think I can help ya' on those casting numbers you need. I just sold a set of those about 6 weeks ago. Wish I'd know then you were needing such. Casting number for left hand BBC exhaust 71-72 402 CI. 2wd are # 3994045 and the number for the right hand side is # 353030 2wd 402 CI. This is per my wife's cousin who is a GM parts man and has been for nearly 24 years. He's my "GM connection" when I have needs or questions on parts. Hope that helps you out, bro.

[hotrodmtodd]

Thanks Big Gar. I have to do some soul searching on this exhaust decision. I have GOT to get this !@#$ Burb home, so I can think straight again. Catch you later brother, MT

[COBRO]

Ttt