Cracked Exhaust Manifold

[Already a Rover]

Hi.  No sooner do I get my starter sorted-out than I spot the crack I was suspecting was there in the exhaust manifold.  Actually, it was WHILE I was sorting it....

Soooo, one solution is to replace with the same, the other is a header!!  I am sure this engine needs to breathe, so was planning on a 2 inch exhaust anyway.  Comments?  Where to find such an animal (exhaust manifold, or preferably a header - if not too expensive)?hav

I've looked online and no obvious source of a header popped up.

The Want List and To Do list are both getting items ticked-off, but are still growing.

Thanks.

jim

[Matt H]

Just use the stock style exhaust manifold. The air cleaner, intake, carb, head and valves in the 2.25L are fairly restrictive and the engine makes most of its power at realitively low RPM so large diameter exhaust won't do you much good and may even adversely effect cylinder scavenging.

You can get a 'gas flowed' head turners engineering in the UK but having never driven a unit with one fitted I can't tell you if it is a big improvement over stock??

[Red90]

I would doubt there are any performance gains to be had with a manifold as I've never heard of it being done.  Even ACR with their expensive PowerPlus kit use the stock manifold, http://www.automotivecomp.com/landrover_perf.html  They do have a manifold, but make no claims, despite putting power claims on everything else. £328  I assume you lose the carb heating, which would be problematic with cold operation.

I think the best chance of a noticeable change would be a properly tuned SU carb or EFI but I would not believe any claim without some proof...  Okay the best chance of a noticeable change would be a different engine.   ;)

For what it is worth, my truck has a Turner gas flowed head, ACR cam and ACR muffler.  I'm in Calgary and you could take it for a spin if you want.  I doubt it is much different than any other 2.25.

[Already a Rover]

Hi Red (and All),

I will PM you my phone number for a ride, as I am staying in town this weekend.

I found some pretty detailed information on air-flow characteristics which should be of interest to all. 

http://www.gunsandrovers.com/showthread.php?t=1241&highlight=allen

Nothing on exhaust flow however, but - yes - the fact I cannot find a header might indicate there is no need for one.

Jim