studied all this years and years ago lads.
a 289/302 windsor is the best option being that it's a 60 deg V8 meaning it's very narrow. this is exactly why other car makes used them in their "hotrod" version in the day. think sunbeam alpine that became the sunbeam tiger, ac ace that became the early shelby cobra, and even the bolwell nagari. in the bolwell case, holden was desparate to have their 308's in them, but they just wouldn't fit.... i know this from my old man and his own bolwell that he's owned since new and his involvement with the nagari's development.
speaking of his bolwell, it's now got a leyland P76 V8 in it, being a slighly bigger version of the rover V8, so i know what i'm talking about here too. the ONLY advantage of the rover/leyland is that it's all alloy, so it's light.... very light. even lighter than a holden red 6!!
as for anything that's 90 deg (chev, holden, rover/leyland, chrysler, ford cleveland, the lot)..... forget it. they are all waaaaaaaaaaaaaay too wide. don't be fooled like most are with the "little rover/leyland"..... mate, they are HUGE. even wider than a SB chev! they are only a small bore and make their capacity in the stroke, meaning a very wide block....
a 351 windsor is 60 deg, but as the block is taller, it also makes it wider across the inlet manifold.... again, too wide.
also forget anything that V6 multi cam.... isuzu included. sure, they are smaller in the block, but the heads are HUGE, and that makes them wider than some V8's!!
most V6's are the same prob. chev, holden, buick, etc are too wide being 90 deg. but a ford capri V6 is 60 deg and would be ideal.... if u can find one!!
youre on the right track tho Rob. ALOT of cutting and shutting is needed. one thing u have missed tho is that alot of work is needed in the pedals area, as the RH head goes straight thru the pedal assembly.... so a whole new pedal box idea is needed.
and yes, a V8 in a Wasp is possible.... and while I'm a thru and thru ford man, trust me when i say a 308 holden sits in a Wasp engine bay veeeeeeerrrrrrrrrryyyyyyy nicely! so liz.... greg doesn't have to worry about check that one now and i better get back to it!!
the towers would have to go. wasp chassis,wasp inner guards, it would look like a bellett sedan 9 inch rear end. 
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