Bigger Throttle Body

[big_blue_chevy2006]

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?

[72 rs]

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

[big_blue_chevy2006]

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

[broughy84]

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.

[big_blue_chevy2006]

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

[383chevyZ71]

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