I've got a line on a set of 300 heads that I'm considering for my TR8 and I'm wondering if there's any real advantage to installing them without any other mods. I know they flow better than the 215 heads, but I'm concerned about losing compression ratio from the already anemic 8.15:1. Is milling an option? Also, will headers match up from the 215's? Thanks. Tom
300 heads I think they are a higher comp. # Go to www.forum.triumphtr7.com for more answers on TR8. Diver
The compression ratio will go way down. You'll be starting with a 39cc and going to 54cc. You probably already know that. Based on my calculations you'll drop 2 points! YIKES. The 300 heads are a great upgrade though. If you are planning a rebuild in the somewhat near future it's worth thinking about the purchase. Something to consider would be getting a set of later Rover heads (4.6/4.0) with the 29cc heads. They don't flow quite as well but better than you've got and you'd get the increased CR... It works out to about 9.25:1.
Losing 2 CR points is not exactly what I had in mind. Of course, my next question is, can they be milled enough to at least maintain the original CR, if not boost it a little?
I don't think you can take enough off. Even if you remove 50 thou your still looking at a reduction in CR. You could consider a rebuild... Maybe you could remove 100 thou... That seems like pushing it. You start running into a bunch of different problems like intake port matching, resizing the pushrods (which would need to be done if you milled the heads at all.) BTW. I went to Door County with my Wife for our honeymoon. You probably hear that a lot...
I was afraid that's what you were going to tell me. Guess it's back to the old 215's for some head work. If you get back to D.C. for another honeymoon, be sure to look me up. Tom
