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View Full Version : performance TBI on stock motor?

87mut
08-14-2007, 10:28 AM
I just put a new long block in my truck, but I am not sure how old the TBI system is. The truck itself has 340,000 miles on it. I am thinking of either just replacing the two injectors, or getting a performance TBI, like the 670cfm from Holley. My question is, if the only modifications I have to the motor are an opened up exhaust, would the performance TBI be a total waste of money? New injectors from what I have found so far are $200 - 300 for both. I found the Holley TBI in JEGS for $419. Would it be worth the little extra for the higher cfm, or will it not make a difference on a stock motor? I mean this in both power and gas mileage.
1realZ71
08-14-2007, 06:46 PM
I just read an article in peterson's 4wd about an aftermarket tbi system that they tried on their dodge 360. They had a lot of good things to say about it so maybe worth trying.If someone has that article on hand maybe they will chime in.
93_gmctruck
08-14-2007, 06:48 PM
i put the 670 cfm on my 93 gmc 1500 with a 5.7 liter motor and i never could get it to work right. talked to holley several times and they were really concerned that the motor had to be stock and mine is. just always had a bad stumble at the hit of the throttle. if you decide to get it good luck with it
1BadZ71Tahoe
08-16-2007, 12:34 PM
i put the 670 cfm on my 93 gmc 1500 with a 5.7 liter motor and i never could get it to work right. talked to holley several times and they were really concerned that the motor had to be stock and mine is. just always had a bad stumble at the hit of the throttle. if you decide to get it good luck with it

Nothing a little tuning and 454 injector pod can't solve. :read:
93_gmctruck
08-16-2007, 04:32 PM
thats the thing though i tried everything and nothing i did would work so i sent it back. have you guys tried anything else to you stock throttle bodies the help them perform better?
90C350
08-18-2007, 07:26 PM
Do a search on the Thirdgen.org site for the ultimate tbi mods!! It does help a little. You can rebuild and modify your stock tbi unit to flow more and run better for the cost of new injectors. I would get a new set of injectors and a rebuild kit for you tbi, Then do the ultimate tbi mods and your done. Those injectors sound a little steeply priced as well?? I can get 2 new flow matched injector's out here in Canada for $140. Just my thoughts on the topic. Hope this helps??