SU's / manifold for the 2.4

Hi guys, which of the following manifolds are best suited for an SU (HD6) conversion on a 2.4 XK engine ?
(a) C14651
(b) C12438

Many thanks

I can’t speak to the part numbers, but the manifold from a 3.4 or 3.8 engine with the B Type head should work fine; so Mk2, S Type. This assumes your 2.4 is not from a 240, which has the straight port head, but would have SUs anyway. There will be some mucking around with coolant to water pump and radiator hoses though, as the shorter block 2.4 will have the manifold mounted lower than in the big block motors. If you expect horsepower improvements from this mod, you may be disappointed, however. In the '50s, Jaguar issued performance improvement kits of various stages, and even with the A Type head and low lift cams of the Mk1, the kits produced ( claimed!) horsepower in excess of the 2.4 Mk2 and with standard high lift cams, more than the 240.

Many thanks Kevin. I am asking for a friend who is building a ‘special’ and he wants to fit SU’s, more for the visual aspect and not for performance. I have the inlet manifolds available in original post but wanted to ? which was best suited should there be a difference in them.

Hi Eugene,
Do you know which models the 2 manifolds are from? I may be able to give more advice then. If it’s going into a special, then space and plumbing constraints may not be an issue. I’ve just had a look on E Bay and both are listed for XK150, Mk2. There are 2 versions, the later one has ( I think) 6 inlet ports for the auxilliary starting carburettor, whereas the earlier had fewer, ( 1 or 2, from memory) If the ASC will used, the later one gives improved cold starting, but if the ASC will not be used there is not much to choose between them. Choose on price and condition.

Kevin one is for the early XK150 and the other for the later XK150 / Mk2 (C14651).

I think the early one had a single feed from the ASC into the bottom of the manifold via a largeish tube, whereas the later one fed 2 branches of 3 each with rubber connections. If you are using a manual choke setup, this will be of no issue, but if you plan of using the ASC, go for the later one. As regards to mating up to the head, there should be no issues. Remember, you need the water rail\ thermostat housing on top as well. Also get as much of the throttle linkage as you can, even if just for parts to mix\n\match.

Thanks Kevin for sharing your knowledge.