A lot can depend on the condition of either set- if they are in the same shape, valve job-wise and such, the X heads will be worth a few HP over the 993.
But if the 993 were in top-notch shape and the X heads were worn out, the 993 would be better.
That said, neither will be all that, but I'd give the nod to the X's, all else being equal. The gains will be at the upper end of the powerband (the main difference AFAIK, is the intake port volume), so you'll not be seeing it w/o running them at the track and charting the ET/speed.
A lot can depend on the condition of either set- if they are in the same shape, valve job-wise and such, the X heads will be worth a few HP over the 993.
But if the 993 were in top-notch shape and the X heads were worn out, the 993 would be better.
That said, neither will be all that, but I'd give the nod to the X's, all else being equal. The gains will be at the upper end of the powerband (the main difference AFAIK, is the intake port volume), so you'll not be seeing it w/o running them at the track and charting the ET/speed.
stock high rise with 1 inch spacer plate 4412 holley carb the 487x have been shaved and totally rebuilt at a high-end machine shop
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Hot Rod Forum
2.2M posts
175.9K members
Since 2001
A forum community dedicated to hot rod owners and enthusiasts. Come join the discussion about restoration, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more!