I see a lot of threads about aftermarket heads, most noticeably AFR Heads. Can someone please explain why these heads are better, especially if they are ported and polished as opposed to ported and polished stock castings. I understand, basically, what porting and polishing accomplishes, I'm just not completely sure why it is generally accepted that porting and polishing aftermarket heads is more desireable.

 

AFR provides a great set of worked heads with decent numbers...a lot of people these days have just been getting their stock LT1 he+.ads ported for the reason that your local porting guy, ie. Lloyd Elliott, can get better flow #'s than the majority of major caompanies at a fraction of the cost...

 

It pretty much boils down to potential.. you can only take the stockers so far. However, what can be done with the stockers by several of the p&p pro's out there is quite impressive and more than meets the goals of most. Folks crack 400+ rhwp with p&p stockers all the time.

 

 

I figured that they had more potential, but my question is more why they have this increased potential.

 

Well, first of all, there is more material to remove on aftermarket heads. AFR heads come pretty well ported, but if you wanted to port them even more, you could do it. Plus the designs of the combustion chambers and such usually tend to be superior on aftermarket castings. Well, it better be, cause they are asking like $2500 for a pair.

 

If up to around 500hp is going to make you happy (it's more than most people ever expect IMO), then I'd work the stock stuff. If you're out to try to make alot of power, then I'd go ahead and spend the additional $1k or so on an aftermarket casting.

People break 400rw all the time? News to me, most of the "27Xcfm" H/C lt1's around here are in the 360-385 SAE range from what I've seen over the past few years.

Of course everyone's "Hoping for 400rw!" when they start on something... maybe there's just more hopefuls out there now

 

For 1k more I could have had a set of AFRS that flowed 300+. But I settled on porting stock castings to net me 290+ Is the extra 1K worth the extra flow numbers? Don't know,maybe I will sell my heads one day and buy a set of AFRs and see how much a difference there really is.

 

Good point, perhaps not all the time.. but I've seen a few on here. Some guy in NC or something has put a few out there I believe

 

290 on stock castings is rare....if even possible...

 

yeah.......my understanding was that 290's arent gonna happen without adding material