any one out there tried one of these ? i have a 88 blazer 5.7 with edelbrock performer tbi intake with a stock tbi on it , holley sells a tbi part #502-6 for this truck , says its better than stock , my concern is that the intake bores are only 1 11/16" same as the stock intake ,holleys tbi has a 2" bore , would that create some sort of fuel restriction ? if the tbi bore is bigger than the intake bore wouldnt the fuel being sprayed into the intake hit the smaller bore and create a drip or restriction ? holley lists it as a direct stock replacement ,any advise would b awesome, thanx

 

Honestly you would be better off getting a stock TBI from a 454 truck. The holley ones are only good if you like to flash names or stickers. Its easier to get parts for the gm units and they use the same basic design as the holley. You can't make me think 2 one actually works better because of the name.

The 454 gm unit has a 2 inch bore and yes to get full gains the intake needs to be bored to match.

 

When I replaced the engine in my '87, I also bought the edelbrock manifold and tried the Holley tbi. Should be plug and play right? Couldn't get it to work. Took it back to the store and got another. Same thing. Finally, broke down and took it to the local shop and they put in a half a day trying to make it work. They even called the Holley tech line. After a week, put on the stock tbi and it's been running great ever since.

 

my buddy had one on his (88 ,350 , w/holley tbi)
it has somekind of control box to "tweak " the fuel settings, and he was constantly messing with it , trying to get it to run properlly , (just like a holley carb)
i would go with a oem if possible !! i was not impressed at all !!!!
this was quite a few years ago (5 or more) and i am seeing that holley has several different systems , now, this is just MY experience with holley injection products ! gm performance has a system , for close to the same price as holley system!