NikwoaC's "Commitment Issues" Engine Build

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by NIKwoaC, Mar 12, 2011.

  1. 90LX, in case there's any confusion, I don't think the motor is going to put out bad numbers at all. Many people speak as if big heads will cripple an small motor, and I completely disagree with that sentiment. To the contrary, though I am inclined to believe that there is a benefit to port velocity, I'm really just discussing the merit of the idea with Nik to help me flesh out or negate relevant points in the argument for and against port velocity. This conversation is actually quite insightful to me. I could just as easily argue the other side and play devil's advocate, and would if someone strongly believed that smaller heads are the only way to go. That said, please feel free to join in. I value your opinion and thus welcome your input. Now, on to your comments.

    Please fill me in on the details on the LS3 heads. I really don't know anything about them. About them being at home on an LQ4/LQ9, I suppose I'll have to take your word for it. Have you any basis for comparison between this head and a conventionally wise smaller head? I really want to see a comparison done.

    About your combo, people are idiots! You had big heads, but you also had a Dart stroker with the potential to rev to the moon. Your motor is in the same boat as mine, though mine is boosted and at lower RPM - a topic I'd also like to know more about. Some claim that boosted motors work better with bigger heads than normal - a belief that I am more strongly inclined to disagree with. That however is another topic worthy of a separate thread, if you'd like to delve into that topic.

    The carb thing is a good point, though in this case the carbs on each motor were identically sized. I'd assume that any advantages from EFI would be present on both motors.

    Yes, again I agree with your point, but the requisite counter point is that these offerings were the best Ford and Chevy could do at the time in the Trans-am program that these companies were spending huge amounts of money trying to one-up each other on. I don't have any quantitative analysis, but my intuition tells me that both heads must have had nearly equivalent efficiency. Today's efficiency would likely affect each in the same way. The 162cc heads on the Chevy likely pale in comparison to an AFR165 today. I think a close comparison would be a similar sized CHI head vs. an AFR165 on the chevy. It would be a fun comparison for the purpose of our argument.

    I just haven't seen, but am dying to see an engine masters challenge that measures only the average power across a 3500-6000 RPM powerband. That, I believe, would definitively answer the question. I know they did something like that this past year, but I don't recall the details, and don't remember the powerband they competed over.

    Kasse was not the only guy working with the CHI heads, but his team is the winningest one.

    Hopefully you've got the magazine and can tell me ;)

    What's ironic to me about the motors is that it looks like the chevy had a high revving cam in their 302 while Ford had a lower revving one. Both motors probably liked to be shifted at around 7k RPM, though. The counterpoint here is that if the Chevy was more mildly cammed, I think we'd see significantly higher numbers down low.

    No idea... could you please explain it to me all over again? :D
  2. I don't have the heads yet, it'll be two weeks or so before the fellas at TEA have everything ready to ship. I'll take plenty of pics and measurements and post them up once I have the heads, but like 90lxcoupe said, I think they're in the 2.200" by 1.600" neighborhood. Actually, I'm looking at the spec sheet right now and it says 2.240" x 1.375".
  3. The LS3 heads are the same as the L92 head, they can be bought for around $1000 bucks and flow in the 320 range with awesome low lift numbers. There have been plenty of 550 hp street motors with these heads and a JY 6.0 shortblock. In fact, i think that combo was entered into an engine masters a couple years back where they used the original bearings from a truck motor and made impressive numbers with it, competing against some high dollar motors.

    Testing The New GM L92 Cylinder Heads - Car Craft Magazine

    From TEA they are even better for a little more money... you could have a cyl head that flows over 350 cfm for $1530
  4. Wow, very impressive at that price. That's what I paid for my used AFR205s :)

    Edit: I read the whole article and still don't see the port volume. Help?
    Re-edit: k, disregard, I googled and see it s 260cc. Pretty big, but roughly equivalent to a 195cc intake on a 6000 RPM 302.
    re-re-edit: whoops miscalculation - actually 190cc is more accurate.
  5. To tell you the truth, i never paid much attention to the port volume, i didnt even realize they were 260, thats huge, but ive read alot of builds using them and i am impressed with each one of them. That cyl head is one of the main reasons i would build a budget LS motor and drop it in a good chassis. Easy(er) way to a 9 second pass
  6. I have 205cc tw heads from TEA on my 331 (though I didnt get the car dynoed until I got the blower on it) it felt alot stronger going from stock cast tw to the 205cc threw the whole power band. The great thing about TEA is they just dont focus on peak flow numbers at 600 lift. They are really big on h mid-range cfm's to get the most out of the power band.
  7. Ive heard TEA does all the CNC work for trick flows out of the box heads
  8. If I remember, I'll look for it tonight. I've been a subscriber to HRM for about 10 years now, so I'm sure it's somewhere.

    See, and that is what the real beauty of this whole big head/small cam logic is. It enables you to have a high revving, high horsepower engine without sacrificing drivability, because you don't have to cam it very aggressively. The Chevy heads weren't capable of moving near the same amount of air as the Boss heads, so they had to make "compromises" in the cam design.

    Haha. I like this thread.
  9. Can you imagine what people would say if you put a 260cc head on a 351 Windsor? They'd poop their pants. "Ahh, it'll be a turd, blah blah blah". Of course, comparing port volume between a SBF and an LS motor is apples and oranges, but still.

    The Chevy guys have it so good, and half of them don't even realize it. :p :nonono:

    I believe this is true.
  10. Yeah, man. My little 331 made 364/372 rwhp (SAE/STD) at a stupid lean 14:1 AFR through a ****-ton of turbo piping, and it was only spun to 6100 RPM, and the timing wasn't even dialed in. Keep in mind that's with 8.5:1 compression. If I were building an n/a motor, it would be closer to 11:1.

    Long tubes, compression, timing, 13:1 AFR and 6500 RPM would've blown 400rwhp out of the water, there's no doubt in my mind. Pretty cool for a 228/224 @ .050" 114LSA cam with a nice idle.

    I wouldn't call the torque number all that impressive for a 331, though 329/336 rwtq (SAE/STD).

  11. My new AFR205 are 1.3 x 2.140. That is right at the mouth and actually change a little smaller going into the push rod pinch area. So a bit smaller then the TW. I know they almost had to be because the port runner is actually shorter on the TW. As Nik pointed out a while back.

  12. FWIW, TEA is owned by TFS is owned by summit:nice:
  13. I imagine the torque was really hurting from the lack of CR and with all the turbo piping. But those power numbers are a testament to those heads being capable of doing awesome things!
  14. Sidebar: Anybody have any recommendations on valve covers? I'm not going with the Trick Flow ones because I don't want it to look like a TFS rep puked on my engine, haha.

    I really like the classic FRPP EFI ones, but they have problems with clearing roller rocks, right?

    My second thought is these Canton units. Just not sure if the polished look will work with anything under my hood.
  15. I have the plain tall summit ones, i like em, check your hood clearance with the R too. you may need a cowl, even without a spacer.
  16. Get a set of the fabbed aluminum covers from the bay. If I had a taller hood I would get a set in a heart beat.
  17. black car, black powdercoated intake with black powdercoated valve covers...
  18. powdercoat is overrated. just use a sharpie.
  19. fabbed ones are nice but usually you'll have to get some baffles welded in
  20. Nik: you have to come to the southside and ride in my 94 gt, we took it out tonight, man 6900rpm feels good lol.