Hi guys, I have a 1985 S10 project truck that I am putting in a 2003 5.3 engine, it's flex Fuel ( I didn't know it when I bought it ). I notched the frame as much as dared too for safety, installed a Holley oil pan and made up some engine and tranny mounts and got it to fit. The fit is tight but it fits. Being a Vortec engine the intake is pretty high, the hood hits the throttle body and the alternator. I am in the process of relocating the alternator to clear but the intake is the big issue, I don't want to put on a fiberglass hood because I want a stock appearance, so I want to swap the intake for a Camaro, Pontiac or Vette to clear the hood. My question is what intake could I use to solve this issue? Also can I use the Flex Fuel injectors ( they may be a different physical size and may not fit ) and the injector connectors are different too. I want to use the original throttle body and as much of the original wiring as possible to avoid issues down the road. Can anyone help or suggest a reasonable solution that won't cost a fortune, any help would be deeply appreciated.
Thank You,

 

Just went through something fairly similar for my non-flex-fuel 5.3 in a Volvo - a lot of guys doing that swap are keeping truck intakes and trimming off some of the webbing if not doing a full "shave", but I wanted to keep a strut tower brace, so went LS1/6 car intake, but wanted to at least pretend I was sticking to budget. All in, it's roughly $750 of mod cascade (without any clever wheeling/dealing, that is):

I got a Dorman LS6 reproduction intake. The truck throttle body and MAP sensor mate, and the vacuum/PCV plumbing differences will work out with standard hoses and tee fittings. The truck carbon canister purge valve (which I'm keeping for some reason) won't be easily reused, so I'm picked up an external valve from the junkyard from a 3800 (which uses the same part as an LS1/LS6). The truck alternator/PS bracket interferes with the vacuum nipple for the purge valve on the Dorman intake (it's a little higher and further forward on real LS1/LS6 intakes, so it probably isn't an issue there), so I modified it to point vertically.

I tried several approaches to hacking the truck fuel rails to work with the LS6 intake, but didn't come up with anything I was happy with. I went ahead and got the Holley fuel rails, so I don't get any "budget build" points here, but I did manage to manage to reuse my truck injectors. Popped the caps off, swapped on normal-Bosch/LS1-injector sized O-rings. Rail mounts flipped upside down, attached with one bolt (of the normal two), at an angle, over 3 1/16" washers.


As far as the belt-driven accessories go:
The truck water pump interferes with the throttle body after switching to the lower intake (the Gen IV truck motors , so I swapped on an L99 (automatic G5 Camaro) water pump. The idler pulley section of the truck alternator/PS bracket interferes with both the throttle body and the water pump, so I cut it off and got a Dirty Dingo idler pulley relocation bracket.

 

Hi vertigosity, thank you for the info, it is very helpful. It doesn't look like it is going to be easy or cheap. I am working on relocating the alternator to the right side of the motor now and noticed the throttle body is only about a 1-1/2" over the water pump but I didn't think much about it, thinking a different intake may have the TB back a bit and it would clear, but since you mentioned the TB hitting the water pump this could be a issue with the swap, I need more than 1-1/2" for the hood to close. I don't want to change the intake and have TB to water pump issues and have to start replacing the water pump and more acc. drives components and pulleys. It looks like I better do a lot more research before I go any further. Thank you again, you saved me a lot of time and probably a lot of money. When you build a hot rod it's one problem after the other and that is what makes it a challenge, but if you ever finish you feel good. You and your family have a nice holiday week end.
PS - I'll post again if I ever resolve this problem, but if you see smoke on the horizon you know what happened.