I have just started to do a little investigation into projected replacement of my 89 740 GL. I just turned 421K miles and don't know how much longer it will last. I haven't found any info on whether the 740 or 240 blocks are the same. Now I have the distributor in head and I believe all of the 240 engines have the dizzy in the block. So my question is can a 240 block take my 740 head and just block off the block dizzy hole. Just asking . Thanks.

 

The block is the same for the 240 and 740. I don't think there is any reason you cannot use a 240 block in a 740 as long as you block off the distributor hole in the 240 block. Or, you could just use the 240 head and distributor. Doesn't matter. I do believe I read somewhere that the 940 and maybe 740 blocks did not have the distributor gear on the half-shaft and therefore cannot drive a block mounted distributor so going 940/740 block into a 240 requires a half-shaft swap.

 

or you can shop at jagsthatrun.com and drop in a small block V8 that'll wake up your 740 :-) Love the fact that you're re refreshing a high mileage keeper !

 

In my youth I've done several V8 conversions . They were all Corvette drive trains in different Jaguar chassis. Those years are over as it's a little to late in life (80) to take on a major project . Just doing a simple OEM swap will only tie up a few days where as a conversion would take a month or 2. My main focus now days is golf and enjoying my C8. I see a lot of 240 short blocks so I'll still look for a 740 but good to know either one will work.

Just one of the conversions on my 100K mile XJS
This is my golf cart and daily driver now.