Big Block Corvette Exhaust Manifolds Wanted

4SPEED427 · A Poncho Legend!

Big Block Corvette Exhaust Manifolds Wanted

73SC · A Poncho Legend!

I sold a pair of BBC manifolds at Queensway for $10 that I was tired of tripping over. I just looked these Corvette ones up and repops are going for over $400 each!!!!!

4SPEED427 · A Poncho Legend!

I checked repros on ebay and after a bit of looking found one side for $80 US and the other side for $98 US. But yes, some guys were asking the prices you mention! Crazy....

DonSSDD · Canadian Poncho Superstar!

Rockauto?

4SPEED427 · A Poncho Legend!

Yes, I checked and their prices weren't the absolute best but very close to it.

However, a friend called me today out of the blue and while we were talking I mentioned needing these. He's pretty sure he has a set for me!

4SPEED427 · A Poncho Legend!

I got a pair of manifolds, they came special delivery to my door this morning!

pontiax · Poncho Master!

two less pieces of the puzzle. It must be dejavous for you.

4SPEED427 · A Poncho Legend!

I'm loving it!

I took the 427 apart this week, got the L72 manifolds, it's all good.

I wonder how much more power these manifolds make vs stock L36 style. I'm betting it would show a difference on a dyno.

68 Grande · Guru

The "How to Hot Rod Big Block Chevys" book by Bill Fisher talks about the Corvette exhaust manifolds. "Corvette have the best exhausts offered on rat motors".

It goes on to say on page 19 "If you are committed to use the iron manifolds and the HP loss which they inevitably cause, you are probably stuck with the manifolds that came on your car because the best manifolds - supplied by Corvettes- won't clear the chassis of other Chevy's."

So, Will the big block Corvette exhaust manifolds work on a 68 B Body? I wonder how much better flow they provide over the log style?

-- Edited by 68 Grande on Sunday 16th of September 2018 07:57:24 PM

4SPEED427 · A Poncho Legend!

They are the standard manifold on 66 L72 B body. In my mind, that tells me that they should work on 65-70 B body.

However, with that said, from what I can find only the 66 L72 used these manifolds in a B body, even though in the US they had it available in 68 and 69 as well as 66. (I have it in my head there is no L72 b body option in 67?) From what I can see, the other years of L72 used the regular 396/427 manifold.

Howmac will hopefully see this and respond, he knows the later L72 cars very well.

Howmac · Guru

Interesting topic ... Carl you may be correct with the statement that if the casting#'s 3880827 LH , and 3880828 Rh fit a 66 B body , then why not 67-70 ? (L72 was not offered in 67 B body)

68-69 B body L72's used the same exhaust as the other 396,427 engines . I assume the rear dump on 3914613 LH was changed to give more clearance for the steering box. Perhaps the Corvette required different manifolds due to engine compartment configuration ( tighter fit?)

4SPEED427 · A Poncho Legend!

68 Grande wrote:

So, Will the big block Corvette exhaust manifolds work on a 68 B Body? I wonder how much better flow they provide over the log style?

-- Edited by 68 Grande on Sunday 16th of September 2018 07:57:24 PM

No chance of you having the manifolds off your car before winter is there? If so, we could test fit these on your car.

68 Grande · Guru

Well, I could come out to Morris in the near future and we remove them and see if they fit the 68 GP. Realistically, it should be the left side that would most likely be the determining factor, would it not?

4SPEED427 · A Poncho Legend!

Yes, I would think the right side has plenty of room.

4SPEED427 · A Poncho Legend!

I'm going to keep reading and asking questions though too. Surely someone has tried this on a big block B body newer than 66.

DANO65 · Poncho Master!

Could the interference be with the updated steering of the 67 and up cars?
Idler arm, pitman arm, center link are different to provide better steering geometry. Could be it moves things just enough that the Corvette manifold wont fit any more?

4SPEED427 · A Poncho Legend!

Next coffee break hopefully I can bring my car and if Jake can bring his 68 maybe a side by side would be helpful.

68 Grande · Guru

The soonest side by side might not happen till Saturday or perhaps one night this week, or later in the week.

4SPEED427 · A Poncho Legend!

A bit of an update to this.

I was talking to Howard (Howmac) today. He said he posted the "will Vette manifolds fit later b bodies" question on another site. Apparently it's been tried and they won't fit later years, as in 69-70, maybe even 68. We agree it must be a steering issue because what else is different?

68 Grande · Guru

So as Dano suggested, there were major changes in the steering box and other parts in 67 on the B Body? What else could it be? It has to be that because every header that gets installed on a 68 B body big block has to end up being pinged or dented to fit around the box. Maybe that is exagerating a bit but even the stock manifolds on the drivers side have been designed to slip around that box.

Don't write me off of coming out to Morris quite yet, I just didn't like the forecast to drive my garage queen out there this weekend. We will solve this definitively (although Howmac already has provided the most likely resourced answer).

4SPEED427 · A Poncho Legend!

Yes, we can wait for nicer days. We're not even close to the end of driving season yet.

When I get some time I'm going into the books to see if I can find any more info but I think you are right, Dano likely has it nailed.

65wagon · Poncho Master!

ive got a simple solution for everyone, dump the whole works and install a power rack, problem solved, yes im tempted.

seventy2plus2 · Canadian Poncho Superstar!

The red 70 2+2 hdtp that comes up on the site occasionally has a 454 in its engine bay, and a Corvette manifold on the passenger side. I suspect a Corvette won't work on the driver's side with the power steering box in the way. If manual steering, maybe.

65Camino · Uber Guru

Does anyone make headers for it ?

seventy2plus2 · Canadian Poncho Superstar!

Re the drivers side and the power steering box being in the way and causing interference. The 70 454 Laurentian was originally manual steering. When Hillar had the exhaust system done, he had a Chevelle style exhaust manifold installed on the driver side, there was no problem as the manual steering box is much smaller.

I sold the car locally, and the buyer indicated he was planning on upgrading to power steering. I provided him the proper 68-70 B body drivers side exhaust manifold. He then got a power steering box, but he was on about he bought a 3 tab box, whereas mine were all 4 tab boxes (I have no idea what the difference is). He said he was able to install the 3 tab power steering box with the Chevelle style drivers side exhaust manifold, there was no interference.

Another note, when I installed the 454 in my 70 2+2 rag (in place of it's original 350 4 bbl) I installed the engine, then bolted on the exhaust manifolds, no problem. However when I installed the 454 in my 70 Parisienne (in place of it's original 350 2bbl) there was no way to get the drivers side exhaust manifold on as the steering box was in the way. We finally lifted the drivers side of the engine about 1", then was easily able to install the exhaust manifold. The difference must have been the engine mount perches, but we really couldn't see any difference.