Exhaust manifold 3500s on 3500

Joerg

New Member
Hi,
My manifolds are cracked. Now I could buy new ones for a 1971-1976 3500s, but I have a 1971 3500 series 1.
Will the manifolds fit my car?
Best regards,
Joerg
 
They will both fit the engine no problem, but the output bore sizes can be different. So check the sizes compared to the exhaust pipe size. In the intervening 50 yrs who knows what has been fitted to your car and what is being offered to you. Has your car got an auto system or an 'S' system? Or even a modified auto system?

Sorry, I can't be any more vague. :rolleyes:
 
The earliest manifolds were only different because they had provision for the AED pipework. If you don't have an AED you don't need to worry about that, and if you have auto downpipes any auto manifold will fit, any they are the same part for both sides.
 
But if you have a manual gearbox (usually 3500S, except USA)the manifold outlets and the down pipes are slightly bigger than the auto units. Manual are 613457 both sides, autos are 602693 R, 612975 L, 602623 both sides for chassis 451-455 suffix D,E
 
I replaced the manifolds on my 3500 (Auto) with SD1 manifolds (larger bore). A new set of down pipes were required (to suit larger bore on manifolds). Here Colin Gould sourced these down pipes (in S/S), along with the reminder of the large bore system in S/S
 
I replaced the manifolds on my 3500 (Auto) with SD1 manifolds (larger bore). A new set of down pipes were required (to suit larger bore on manifolds). Here Colin Gould sourced these down pipes (in S/S), along with the reminder of the large bore system in S/S

So you had twin downpipes each side coming down at about 45 degrees towards the bulkhead, joining into a single pipe each side?
I had thought about doing that but never thought there would be enough clearance.
 
Hi,
My manifolds are cracked. Now I could buy new ones for a 1971-1976 3500s, but I have a 1971 3500 series 1.
Will the manifolds fit my car?
Best regards,
Joerg
Hi, I used 3500s manifolds on my series 1. I purchased new ones from JR Wadhams. I purchased a stainless steel exhaust from PD Gough. It fitted excellently. Good luck.
 
So you had twin downpipes each side coming down at about 45 degrees towards the bulkhead, joining into a single pipe each side?
I had thought about doing that but never thought there would be enough clearance.
Sorry Harvey, just re-read my post. I used 3500s manifolds (not SD1) - typo.
I had hoped to try SD1 manifolds and discussed with the exhaust fabricator, but clearance was an issue as you rightly say. My engine is 3.9 and considered the larger 'S' series manifolds to be more efficient.
 
I gave up on standard exhausts as the mountain roads i was driving on kept cracking the cross pipe. Currently have four into two into one extractors on both sides joining into a 2 1/2" main which goes into a very long 4" round muffler that just fits down the side of the tunnel. I skipped the second can over the axles and used a 2 1/2" final resonator in the usual exit position. This (somewhat noisy) arrangement made a noticable difference to the power right through the rev range.

The problem with the Non P6 manifolds is they normally have the downpipes at or toward the rear and the downpipe space on the P6B is very small and central to the head. consequently there is no space available to run the pipes off the manifold and down the tunnel. the Auto cars even have the exhaust running under the sump for the cross over.

Exhaust fitters will be able to weld on larger fittings if required. They don't cost much.
 
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