Holley claimes there 670cfm TB will not even support 300hp?? And as far as I've seen this is as good as TBI gets using the factory ECM. I swear I saw a Holley 4bbl TB somewhere that was set up for the factory GM ECM, anyone know anything about this? I really want to keep the fuel injection and TBI is whats on the car, if I do change it, it will be to a carb.
Do any of you have any dyno results of 300+hp? Man, if I can't get over 300hp with TBI I'll be outrun by Hondas and Nissians. Someone give me some insight on this.......Thanks, Bobby

 

this was holley's response

one of the mebers on the DIY board, is running a 4bbl TBI setup on the factory computer, he build his own secondary injector driver board.

btw, even with 300hp, there are plenty of nissans that will beat you

 

I don't know if anyone has actual dyno numbers. If I remember correctly, there was a member a while back that was making 318hp out of his 350 and TBI. If trap speeds are worth anything, then there are a few of us that should be hitting over 300hp. LS1 f-body engines were rated 315hp-325hp. Most of the near stock LS1 f-bodies at the track run around 103mph. JPrevost ran at 102mph a while ago, I am sure he is well above that now. I ran at 105mph on a reletively untuned chip. And Pablo was running at 103mph with a carb, I am confident he will match it when he get's his tbi running on it.

 

Most LS1's dyno between 290 and 320 at the wheels stock so they are closer to 350hp. GM ratings should have been rear wheel numbers. In addition, they are a few hundred pounds heavier than a thirdgen so I would say most N/A TBI's that are in the 13's are right at the 300hp level. 300hp is achievable with the 670TBI no problem, just like the members you pointed out have. Now for how much you can take it past that is the question.

 

Dewey316 I know there is a lot of Nissans out there that can beat me at 300hp, I have one in my yard a '91SER running a 75hp shot of NOS Hell it hangs at my '97 Zs back bumper untill 120mph. The SR20 is one of my favorite motors, I fully believe close to 300hp NA is posable with it. I've had this one since high school. Got it new for gradwtion. But my hearts with Chevy!!!

 

If I can find that site that had that 4bbl TB I'll let ya know. I would really like that. It was the 700cfm 4bbl TB I saw, it came with a chip and all wires to adapt to the stock GM ECM. I thought I saved it in my favs but now I can't find it. If anyone sees or hears anything on this let me know.
I've got my #3970010 high nickle 4-bolt block in the shop today. I'm getting it bored .060 over and going with a 3.75 stroker crank. Using the aluminum Vortec(2.00-1.55) heads, Air Gap intake(R90CamaroRS your using this huh? What do you think?) Going back all roller cam(not sure which one yet?),lifters(Comp Cams) and rocker arms(Comp Cams Pro Magnum). Moroso 6qt street/strip oil pan with windage tray and crank scraper, Cloyes true double roller chain. Thinking about getting a Eagle 383 5.7 rod Comp Assembly(crank,pistons,rings,rods all balanced). Anyone ever used Eagle? Maybe even top it off with about 125hp of NOS.
I just don't know if the Holley 670cfm TBI will support this, what do ya think?...............................Thanks, Bobby

 

i think if you cam that the way it should be, that 670 isn't going to be even close to enough. (thats a good thing right?)

another note, when you use the moroso crank scraper/windage tray. a couple of notes for you, the crank scraper won't work right out of the box, it is designed for a shorter stroke, you will need the cutoff disk to get it to fit. and with the windage tray rember to leave the holes that are large open, don't put a stud in them. these are for your dip stick. you will be amazed how many dipsticks you can bend when trying to figure out a stupid issue like that

as for eagle, i have heard good things, we just finished my friends, 383 (forged eagle crank, eagle rods, trw forged pistons, mini-ram, afr heads, ect) it was proffesionaly balanced, and it was SO smooth we were running on 7cyl (injector plug came off) and we didn't even know, it was that smooth and precise.

 

So I'm probley going to have to go with a carb(750cfm Barry Grant), huh? I'd so much like the ease of fuel injection though???? Thanks, Bobby

 

the 4bbl TBI is an option. you have ALOT of motor there, if cammed correctly you can make some serious HP.

 

Dewey is right. Check out last months article on the 355 they built with tis set-up. Although the same set-up with a carb produced slightly more power, they are switching cms to be a little more EFI firendly and should be way over the 400hp mark. They will cover this in the next issue that should be out here in a week or two.

 

What article? What issue are you talking about, a magazine?

 

yes it was in Hot Rod magazine in their october issue I believe. I am not near it now so I cannot tell you for sure. I think it was the issue that had the 427 ZL1 SS on the cover.