Bigger Throttle Body

i have a 90 halfton with a 350 tbi. theres a 670cfm throttle body im wanting to buy for 350 bucks its made by holley. they make it for a 87 through 89 5.7l. the questions i have are- i thought 87 was carburated, is it or not? and also would it fit on my 90, i mean whats the difference between a 88 and 89 tbi and a 90 tbi? i have thought about goin to jegs and asking bc thats where it is but i havnt had the time to make it there yet. anyone know?

87 are tbi also........... uses the same motor and tranny as the 88 and up.

ok well then wuts the difference between the 88,89 motor and the 90 motor?

There is absolutely no difference in these engines. A 1987 350 TBI will interchange with a 1995 350 TBI infact. They didn't change anything until 1996 when they went to the "VORTEC" engines. The only difference with anything from 87 to 95 c/k drive train is the transmission. GM dropped the 700r4 in 1992 and picked up the 4L60E in 1993.

ok well then if theres no difference i should be able to buy the 670cfm tbi then right?

The only difference should be the wiring on your throttle position sensor
the older factory TBI had an ovel shaped plug which the Holley has and the newer ones had a round sensor. Also the 93 and later had duel nut breathers. I put one on my 92 model with 383 stroker, also added a spacer and had the intake bored out to two inches to match the Holley TBI. I bought a wire harness to splice on for around 10-15 dollars. Just go to the web page below and tell them what you need. You may also need to get a different bolt from the parts store for a couple dollars for the breather if the holley doesn't come with on.
www.affordable-fuel-injection.com