Vortec to 383

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

98k2500

OBS Enthusiast
Joined
Apr 14, 2021
Messages
89
Reaction score
37
Location
Upstate NY
I'm learning so don't laugh. So let's say you remove your 5.7 vortec and have it bored for a 383 build.

I've read the stock injectors on the vortec are a limiting factor for power gains.

If you buy different heads you need a different intake so then what fuel injectors would you need to buy and would everything wire up to the stock harness?
 

Donald Mitchell

1990 C1500 5.7L
Joined
Sep 24, 2019
Messages
783
Reaction score
1,083
Location
Tennessee
That's a good question. If money were no concern most would use the Holley Sniper, but if your talking factory EFI then I have no idea. If it were me I would be looking into a carburetor/intake setup that would work well with the heads and cam you pick.
 

GoToGuy

I'm Awesome
Joined
Sep 16, 2020
Messages
2,934
Reaction score
3,409
Location
CAL
I plan on doing a 383 upgrade for my 98 4dr Tahoe. According to GM they offer a 383 engine to drop in. Using your existing fuel setup. The computer makes any adjustments for the increased displacement. A change in compression ratio and or cam would need further research.
 

L31MaxExpress

I'm Awesome
Joined
Apr 21, 2018
Messages
5,890
Reaction score
7,539
Location
DFW, TX
You can get an upgraded spider but they are a little spendy. Even a stock 350 needs some manifold porting work. Cammed 305 even responded to the ported manifold. 425-450 is about the limit of the stock injectors running them at 75 psi.
 

GoToGuy

I'm Awesome
Joined
Sep 16, 2020
Messages
2,934
Reaction score
3,409
Location
CAL
So i have a new Delphi upgraded injector set-up. A 383 vortec style engine. The wife gave me some shorty Ceramic headers for Christmass. MSD distributor and multispark ignition sys. A radiator like the one in my K2500. Same dimensions but 4 row. A few other factory things I borrowed off some of the heavy duty options and installed. So originally the Tahoe was close to 300 horses when new. When completed if i get 325 horses I will be happy. It won't ever be a towing machine, just 4 or 5 in comfort. Or me lighting the tires up when i can get away with it. Sorry my foot slipped..
 

98k2500

OBS Enthusiast
Joined
Apr 14, 2021
Messages
89
Reaction score
37
Location
Upstate NY
You can get an upgraded spider but they are a little spendy. Even a stock 350 needs some manifold porting work. Cammed 305 even responded to the ported manifold. 425-450 is about the limit of the stock injectors running them at 75 psi.
What do they normally run at and how do you run them at 75psi?
 
Top