AFR vs Vortec vs ?

[dyeager535]

You've got a lot of specs, and what you don't have is probably available (finding reputable/repeated L31 head flow specs has been tough), so have you used something like desktop dyno or anything to game out the parts? Would make a lot of sense if you plan on using components later, in a 383.

I forgot the 383 part, I wouldn't think of TPI with a 383 personally, although I know some have, the limitations of TPI will hinder the motor, and if thats the case, whats the point of the larger motor?

You might be able to do an LT1 intake swap, etc., etc., but that too starts to be a lot of work. When working with the Gen1 SBC, I think it's prudent to stick with heads that use the "old" intake bolt pattern, as there are more parts available (mainly heads, but intakes too) for them. Aftermarket heads with the non-Vortec ports flow as good or better than Vortec's, so that's not really a factor.

 

[Greg Ducato]

I have not put these numbers through any program, as this is not really a peak power/1/4 mile combination but more grunt duty at less than 4500 rpm for the most part. Real world experience means a lot to me and I appreciate everyones posts in helping make my choices.

 

[dyeager535]

I don't know about the new programs, but at least desktop dyno 2000 (DD2K) shows you the power curve. You don't have to focus on peaks, you can really look at the low end numbers. Here are some really old ones I worked up: http://dyeager535.topcities.com/miscpics.html

 

[Greg Ducato]

Thanks, that looks like something I could spend a lot of time playing around with

 

[folkenheath]

I replaced them with a set of Darts and haven't looked back. (The Darts where still cheaper than the AFRs but very similar in flow numbers.)

And most Dart heads use a stronger base casting material (C355-T61) than either the AFR or the patriot heads. And if you get the dart CNC then look out, but those are big bucks.

Thanks for all the comments and opinions guys, just what I was looking for. If anyone has a similar build or engine please fell free to comment. The top end I use on this engine will probably be applied to a 383 down the road so that does factor into my choices.

If that's the case then you need to decide which is more important, the 350 or the 383, I would want a cylinder head closer to 200 cc for a decent 383, unless it was going to be a mild 383 under 400 hp, then you could probably stick with around 180 cc heads. You may have to sacrifice a little low end on the 350 to make a better power/torque curve on the 383. But if that low end is more important than whatever you do to the 350 will have lower power band once you put that stroker crank in it, which you will like either way.

 

[Greg Ducato]

Yes sir, the 383 will be a low rpm engine as well, thank you for all the good info

 

[82355]

Ebke owns a flow bench (80'427).'

Martin

 

[4X4HIGH]

So you are saying that since your 454 TBI equipped "built" 355 with 202 degrees of intake duration runs good, AFR is the best out there?

AFR is an excellent head yes, good quality, excellent machining, and made in USA. I never said they were bad. But saying they are the best out there is a pretty biased opinion that isn't really based on facts. If you go to the race track and see what makes the most power and runs the fastest, it isn't AFR. And they aren't the only head company with CNC porting. Many people aren't looking for the most power though, and AFR is a good head, no doubt about it.

No, i'm saying it based on my prior 22 years as a professional automotive machinist.

 

[y5mgisi]

Good thread.

 

[folkenheath]

No, i'm saying it based on my prior 22 years as a professional automotive machinist.

I'm surprised it took you 6 days to point that out, you usually volunteer that information much quicker. I won't argue with you on this one any further. If you want to continue to say "AFR is FAR superior to any other aluminum head out there today", that's fine, worst case people might pay more for less power, but they are quality heads so no harm/no foul. It's when you try to tell people to set their timing wrong, or that they can run unleaded fuel in stock heads older than 71/72, or other major issues, that I can't let it go.

 

[bp71k5]

I'm surprised it took you 6 days to point that out, you usually volunteer that information much quicker. I won't argue with you on this one any further. If you want to continue to say "AFR is FAR superior to any other aluminum head out there today", that's fine, worst case people might pay more for less power, but they are quality heads so no harm/no foul. It's when you try to tell people to set their timing wrong, or that they can run unleaded fuel in stock heads older than 71/72, or other major issues, that I can't let it go.

What the?

You call him out for being "biased" in believing one head design is better than others. Not sure how he can be biased unless he works for AFR (he doesn't). Then when he responds with the reason for his opinion (practical experience) you attack him for some timing and unleaded fuel recommendations he never mentioned anything about? I may be biased since Scott built my engine (along with quite a few other people I know), it sounds like the bias is pointed the wrong way...