I am going to put a 350 in, with the FIRST intake, and AFR heads, but not sure which AFR's to go with. Or which cam and headers, although id like to steer away from long tubes. I'd like to go fast as possible but still drive on the street some. What do you guys think?

Or I should say the most efficient heads and cam.

 

Pretty vague question.
How big is your budget?
How much drivability ( rough idle / bad fuel economy , etc ) are you prepared to give up in order to go "fast".
Are you prepared to change stall and gears to suit hotter cam required to make Hp?

Why?
LT's work best

 

AFR heads are the best, they also are expensive. If you can afford it, buy the AFR 195cc Elimentator heads. Get a cam near 224*/230* duration @ .05 lift and 114 LSA. The 114 LSA is for a car with an ECM; its computer friendly. And go with 1 3/4" headers, and why not long tube headers as vetteoz asks. BTW: I think that the SLP headers are shorties. If its a TPI setup, then get the large tube runners, and port match everything.

 

AFR 195's without a doubt. Depending on your pocket book as to which one.

 

well as far as the LT's i dont want to deal with ground clearance or custom fabbing the whole exhaust. really i want a bad a$$ daily driver, so the loss of some drivability is ok. just not too much.
can you still get the slp headers anymore?

and i dont have a lot of money, but i just save for as long as i need and buy one piece at a time. so not too worried about the prices just dont want to spend a fortune.

 

and i plan on changing trans and gears, but down the road. along with suspension too.
would these afr heads work along with this lt4 cam?

http://www.summitracing.com/parts/AFR-1095/

http://www.summitracing.com/parts/NAL-24502586/

 

Those are the right heads. However, for price, check out comparable Trick Flow heads from Summit Racing (my favorite place, I use to live 20-25 minutes from their Tallamadge Ohio store) or Patriot Performance heads. The cam looks good too.

 

For a 350 wouldn't AFR 180's be a better choice due to high intake port velocity? Heck, they are AFR's so either one will be great.

 

Long tube headers will not add much if anything. Read "Engine Dyno Results Are In *Added Flow Numbers*" posted by 1989GTATransAm. He took his new engine to a dyno and tested it with a carb & Victor Jr intake to see what it would do before he puts it in the car and installs his modded tpi. He tested it with Dyno Don's shorty headers and long tubes for comparison. The long tubes increased his power by 2hp at the flywheel. Is 2 hp worth the clearance problems to you?

 

Hi Blueyerocz. I’m going to build a strong 350 with FIRST also and have been looking into AFR’s. From what I can gather, either AFR 180 or 195’s would work great. I think the differences between them in the end won’t be much.

Rule of thumb for street cars is to get heads with highest flow for smallest port volume. The 180’s fit this bill with 260 cfm at 0.5” lift. This would be a match in heaven for 350 with FIRST. Although 195’s are larger, they have great port velocity. 195’s seem to be the jack of all trades and are primarily recommended by AFR for most builds. Some people say that increased flow of 195’s are worth the minimal velocity/throttle response loss over 180’s especially on TPI systems where torque is abundant. Plus 195’s would allow you to grow 350 with different intakes or stroke it to 383. 180’s still flow great and have been used on larger engines. I’m curious about port velocity between the two heads. I will probably call up AFR and talk to them to see what they suggest.

Interestingly AFR has some dyno #’s on a 383 with 180’s and then 195’s. Cam used has duration of 288 (236/242 at 0.05”) which is probably comparable to a 268 duration cam on 350. AFR 195 engine produced 20hp and 16ftlbs more than 180’s. Difference might be less on 350 since air requirements aren’t as great. Only issue I have with dyno’s is that I can’t tell if different manifolds were used. http://www.airflowresearch.com/chevy_dyno.php

From what I’ve read from other members experiences (1989GTATransAm), cams with specs like Comp Cam XFI 268 generate lots of power and is still tame for street use. Anything more aggressive than that seems to be a pain tuning. http://www.jegs.com/i/Comp-Cams/249/...ductId=757952#

As far as headers, I agree that long tubes won’t yield a significant increase over a good pair of shorties. Long tubes will have low ground clearance plus you can’t use air emission equipment. Are you planning on changing transmission from 700r to another kind? Also 3.23 or 3.42 seem to be the best gears for TPI setup. You will be making around 420HP and 450ftlbs at the flywheel. At this level I don’t believe even an upgraded stock rear end will hold up. If you keep an auto transmission with no drags slicks it might be ok. Rear end is a gray area for me now as to what I will do in future. Although this article is for a midily modified 5.0 mustang, I found comparison between short and long headers interesting. http://www.mustang50magazine.com/tec...est/index.html

Forgot to add that AFR now has a vortec 190 head. Flows same as regular 195 but 5cc's less volume.

 

The cams and carb were different in the tests sited above, which could explain the difference. David Vizard showed time and time again that you should go with the smallest port you can to supply your engine to get peak HP and torque.

 

I appreciate the info. And totally agree. I've thinking about using the tko600 or a built 700r4 or 4l60, not sure which yet, because i know manual will be fun but the auto will be faster. And then probably a moser 12 bolt. of course all will take some time to save for, but well worth it in the end. oh plus i've been considering dyno don's headers and y pipe, anyone had good results with them?

 

wildyoung, thanks for pointing out different cams. Carbs look the same. Cam is a little more agressive for 195's to probably take advantage of higher flows. Would be neat to see 195 engine dyno with same cam as 180.

I started to discuss this a bit in the FIRST GP thread but I'll add it here. I'm trying to figure out how much flow a 350 engine would require to help pick heads. I did a rough calc and came up with 350 needing 607cfm of air at 6,000rpm. I believe FIRST flows 300 cfm but not sure if that is per individual runner or for half of unit (4 runners). Also not sure about head flow. For 180's that flow 260 cfm, is that per intake or for entire head (4 intakes)? Could you then say that 304 cfm (607/2) is flow that one head and runner side would need to flow for 350 engine to get all air it needs at 6,000rpm? I think I am missing something here (I'm not worrying about volumetric efficiency). If so, you would need to get 195 supercomp heads.

 

When they rate flow on a head it is per valve. So, for the 180's you are getting 260 CFM per cylinder in intake flow.

I would assume that the FIRST intake is also using the same method to measure airflow; therefore it is capable of delivery 300 CFM to each cylinder.

For your calculation of a 350 needing 607 CFM at 6,000 RPM is the same number I cam up with using the formula below. However, be aware that this does not take into account density of the air.

Displacement/2 X peak RPM /1728

350/2= 175
175 x 6,000 RPM = 1,050,000
1,050,000 /178 = 607.638 CFM

 

Net cam effect becomes bigger in a smaller engine; would be more comparable with a 292 or bigger in a 350
The 236/242 quoted is similar specs to the GM 847 cam; one of the biggest guys run in street 350's with good engine mods and man/ big stall and gears

 

If you read the sticky "Quest for a better flowing tpi" at the top of the board, virtually all of the engines tested in So Cal were running Dyno on's headers. Allen's 396 small block that he just dyno tested with a carb and Victor Jr intake prior to installing and putting on his modded tpi was using Dyno Don's headers when it put out 524hp & 471tq on the dyno. Long tube headers managed to squeeze out 526hp.

 

http://www.gofastnews.com/board/tech...t-volumes.html

I came across this great article by David Vizard regarding port size versus velocity. They tested Dart Pro 1 180, 200, 215 and 230 heads on a 383 engine. Has a nice chart near end showing what head size you want for your power level.

In looking at head flow numbers, most heads seem to level off after 0.50" lift. AFR 180's flow 260cfm where 195's flow 275cfm at 0.50" lift. AFR 195's have 8.3% larger volume but only 5.8% greater flow than 180's. Also with port energy equation, if 195's decreased port velocity by 2% over 180's, port energy would be decreased 14%. All of this is making me lean more towards 180's for a 350.

edit- I think that velocity difference between two heads would have to be significant for port energy to noticeably drop. We know that both heads work great. I believe that it comes down to how much cam lift you are running. 180's flow flatline after 0.50" lift where 195's keep increasing (see flow#'s in links below). From 0.50" to 0.60" lift, 180's increase flow by 3cfm while 195's increase by 20cfm.

180 flow #'s http://www.airflowresearch.com/artic...le115/A-P3.htm
195 flow #'s http://www.gofastnews.com/board/tech...er-masses.html

 

Editing this post since I have correct cross sectional areas from member anesthes.

AFR 180 eliminators have csa of 1.92", flow 264 cfm at .500 for a velocity of 137. The AFR 195 eliminators have csa of 2.18", flow 278 CFM @ .500 lift for a velocity of 127. Missing some unit conversion but this means that 195's have about 8% less velocity than 180's. I think it will still come down to if you have cam lift above 0.50".

 

180's may make more torque but 195's will deliver more power over 5000 rpm. First TPI is good to about 5500 i suppose, so either head choice is fine.

Dyno Don shorties would be a great idea. Longtubes just suck for exhaust clearance but can be done.

AFR heads using one of the XFI grinds like the 268 or a custom setup I call the 276 XFI, just the 224/230 setup. I dont know why comp doesnt offer it off the shelf but shouldnt cost more to have it made, as they have the lobes. Should be an ok grind in a First TPI setup, even better on a HSR/miniram 350-355