Matt, there is nothing significantly different between a later XK120 engine (with studs at front of camcovers) and the SE variant. The SE engine gets new 3/8" lift camshafts (C.5717 and C.5718), a lightened flywheel (C.5808), a revised harmonic balancer (C.5809) and dual exhaust system, plus of course the stamped in -8S suffix on the engine number. But the cylinder head itself is the same, as are essentially all the bolt-ons age for age such as inlet manifold and carburetters. So look for an XK120 head with late-W or any-F prefix, or indeed a Mark VII head with late-A, B or D prefix, or indeed an XK140 head with G prefix (but not -8S suffix denoting on XK140s having a C-type head). If you get a non SE XK120 or Mark VII head, if you want to upgrade to SE spec, not all that hard to find the SE camshafts to install.
Service Bulletin 95 (of June 1951) details what was entailed in upgrading standard engine to SE spec, albeit not then called that, but basically something easily done during the course of a head-off refurbishment.
It is likely that any surviving had has been rebuilt, perhaps several times, and worth pointing out that there are quite a few production changes in cyl heads/valve train to be considered, and that prior owners may or many not have done changes, properly or not, with superceding parts, or not. Examples: stud length, valve springs, valve and seat size, valve stem length, chamfered cam follower guides necessary for the 3/8 cams. A thorough inspection of all parts, as well as a list of what to look for from the Technical Service Bulletins is advised. Another example: Care must be taken with cam bearing caps which were machined (line bored) for each cyl head, and numbered on cap, and head surface: they must be installed only in the exact proper location.,Cracking or losing one is a major disaster. Nick
So the engine I have was made right after yours? Whats the chances of that!!! The data plate on the car specifies engine F3192-8. The original engine/trans in my car was either removed in California, where the car was sold new, Or here in Ohio. Makes me wonder if it is out there somewhere in another Jag. Most likely it was scrapped because Someone started a V-8 swap in the 60’s and lost interest. The car sat a good 20 yrs until my Dad bought it.
interesting things to be found on these old Jags: lost and maybe somewhere is my old car…wrecked in 1964 in So calif…and in a yard…it is …a 54 xk120 OTS, .675880 S, eng F3499-8 probably S.
Hi Roger, seems you really know a lot about Jag’s. Could you please help here: XK140 history confusion - need your help
Thanks!!