Hey guys, first post here. Google kept sending me here for answers to my questions so I figured its a good place. I'm reviving a 1971 Jaguar XJ6 which I'm installing a 350 into to replace the 305 that is in there now. I pulled off the heads for the 350 and the casting number is 3951598. Much to my surprise they are Chevy 400 sbc heads around 76cc with 1.60 exhaust valves and 1.94 intakes. The 305 heads I have are 14014416 with 58cc chambers, 1.84/1.50 valves. I know I'm bumping up compression. The Jag is heavy at 3800 lbs so torque off the line would be nice which the small valves would help with. Punching them out to 1.94 would help the top end but would probably not be in the budget. The 350 I'm planning installing one of these heads in has flat top pistons but is a fairly low compression motor. It is bored 60 over making it a 361 if that makes much of a difference. Due to the Jag's frame rails, I'm limited to a rams horn exhaust manifold but its connected to a fairly free exhaust. I'm not sure how the rams horns factor into the equation. I'm broke and these are the two options I have. I can't afford much machine work on the heads so I'd probably install them as is. Both heads were pulled off running engines so I'm hoping they'll be still okay when I install them on the 350. Thanks for the input guys!