The AFR's are $400 more than the Pro Toplines. How much of a difference will this make on a 383 TPI? I'm not worried too much about the weight issue (i.e. Aluminum vs Iron) but in how they flow. Will this also alter cam selection? I've already got a cam picked out if I go with AFR's (XR276). Would it work well with P/T's too? I'll be running a heavily ported TPI setup unless I can find a way to make the Stealth Ram street legal.

-Rippin

 

i did some excel spreadsheets on those 2 heads. the AFR had better overall flow. but can't beat the price on the pro-topline heads. but i went with the dart pro1 200cc aluminum heads anyway.

side note: the HSR is "street" legal. just not "emissions" legal.

here's what my setup will be. here's what my setup will be.

 

Thanks for the reply! Good call about the street/emissions thing. So overall, the Pro Toplines would be a better choice? What CC combustion chambers would you recommend for a street car, I only want to run 93 octane so that puts me around ~9.8-10.4:1?

Anyone have any info about the cam I was talking about? Such as how it will run in a 383 w/ Pro Topline

-Rippin

 

i'm using SRP 16cc dished pistons with 64cc heads. puts me at 9.8:1 the cam you picked has a lsa of 110* while this should net at least 15" of vacuum, you're pushing it. i would use the xm276hr (112* lsa)or the nx276hr (113* lsa) to ensure enough vacuum so the computer doesn't 'freak out'.

 

Cool thing about aluminum heads though is they get rid of heat a lot quicker than cast so you can run more compression. I'm planning on running near 11:1 with 93 octane.

 

Ditto that..
I know you said you do not care about weight savings but it makes you faster ... 70 lbs is alot.
Also the Long runner as well as the HSR will like the smaller runner size much better. You may even want to go with the 190 AFR..
Another thing you want to look at is the AFR's flow really good exhaust and great mid lift flow.
Can you tell I love my AFR's?

 

Yep, I've seen carb motors go up to 12:1 with 93 octane... I wouldn't recommend it I'm willing to bet it was a bitch to tune.

Rule of thumb you can run 1 more Compression point over Cast when using Aluminum heads at the same octane. Tests have shown 1 compression point is worth 30 hp (Hot Rod or Car Craft did a dyno test on it).

My 210cc RR AFR heads cost me 1550 to my door. They said 1475 in the catalog, so you're not looking at much of a mark up over that considering the shipping weight of the heads.

 

I didn't know it was a 70lb difference! Holy crap.

mrr23: I haven't looked up the specs yet, but do those cams have the same specs as the XR276, just different LSA?

Any ideas of rwhp/tq with a 383, Pro Toplines, XM276HR? I like your compression ratio, so maybe you're same setup as far as head CC and pistons.

 

yes all the same except LSA. i'll be using the comp cams 07-305-8 (220/230 @ .050 .510/.510 --adding 1.6 rockers brings it to .544/.544) according to DD2003 441hp @ 5500 and 457tq @ 4500. but we'll see once it's on the dyno in feb '04.

but look what happens when i go from the 07-305-8 to the 07-306-8 (230/244 @ .050 .510/.540 with 1.5 rockers):

HP http://stealthram.com/dyno/305306comparehp.gif

TQ http://stealthram.com/dyno/305306comparetq.gif

lots of loss under 4500 rpm. but the larger cam picks up above 4500. so, pick your rpm you want to use.

 

Don't forget about Brodix!



Also, don't worry about vacuum at idle... Low vacuum at idle can easily be tuned around (with SD at least). It will limit your brake boost and whatnot just like a carbed application with low vacuum though....

 

I think I want to go over 4500, so I geuss the 07-306-8. 441 fwhp would be around 375 rw assuming 15% drivetrain loss. That's nuts! I was expecting maybe 300rwhp. Sweeet! Do the Pro Toplines flow just as well as your heads? Even close?

 

yes they will flow close. with the exception that i'll be using 2.055 intake valve. if you go with the 306 cam, make sure you gear the car accordingly. at least a 4 series gear (4.11, 4.56, etc.) but my question is why turn so much RPM when you can make the same power lower? this cam was in my friends 383 (which i'm buying). he shifted at 6200. and the 306 will be making less power until 4500 than the 305 cam.