305 TBI Header (?)s

[89Sierra305]

I have an 1989 GMC Sierra 2WD with the 305 TBI (not Vortec). It's a SCLB. I bought the truck from some guy who was going to strip it for parts for another truck but he ran into some interchangeability issues and changed his mind before he even got into it. Anyway the engine threw a rod on me after I did a basic tune up (fluids, cap and rotor, wires, and plugs). He later revealed to me that it was sitting for 10y before I bought it. So I sourced a rebuilt 305 from Powertrain Products with a decent warranty. Before anyone says I should have done a 350 swap, I wanted to but my area junkyards didn't have one and the company I ordered from didn't have any ready (6 week wait opposed to ready to ship for the 305). So that's where I'm at. I don't want a race truck. I just want to wake up the little 305. I've been searching this and other forums for options. I plan on doing the ultimate TBI upgrades maybe a mild cam and some exhaust. My end goal is just a good old "gettin to town rig" like Derek from Vice Grip Garage says. Something someone can look at and say "that's a nice truck." I want to make her breathe better first. I hear from alot of people here that long tube headers is the way to go but I couldn't find anyone who did it to the 305. I can do shorties but I hear that if you plan on doing a cam you might as well get LT. Anyone have any ideas on some easy(ish) fitting options with some links? If I'm going with a mild cam upgrade can I get away with shorties?

 

[Das Hatt]

If you're willing to go as far as camming a Tbi 305, I would suggest saving up and waiting to do a 350 swap and proceeding from there. Period. The shorties and Ultimate Tbi model are just nibbling around the edges. Start with a good power plant.

Now if you're unwilling or unable to swap the 350, Shorty headers are only one part of the very restrictive exhaust. They won't get you much on their own. You need to do the Y pipe and rest of the exhaust to see any gain from doing the headers. After the exhaust you can do the TBI mod, maybe take the heads off and have the intake side ported. Then you can worry about a new cam.

Stepping aside from the motor for a moment, if your rear end is a 3.08, you can step up to a 3.73 to give it some more acceleration. Won't help your fuel economy at all, but it's something to consider.

 

[95burban]

I would do exhaust(shortys and a high flowing y pipe or true duals), tbi mods(fuel spring and maybe a spacer), give it some timing and a set of 3.73 gears. It would be a decent running truck that will spin the tires at will. A cam will require tuning for it to run correctly.

 

[89Sierra305]

Thanks for your answers. I'm staying with the 305 for now since it is basically brand new and ate my savings acct with the new motor and install. I'm not saying a 350 swap is not completely off the table though, but it is not doable atm. All the local truck guys around here are holding on to them for dear life lol. And junk yards around here are fresh out and have been for awhile now. And FB marketplace options are all clapped out and needing rebuilds. So for the next 200,000-300,000 miles I'm rockin the 305. I may just do an exhaust upgrade and leave it at that. Again thanks for the reply.

 

[Erik the Awful]

If you're short on cash, spending what little you do have to upgrade a 305 is peeing in the wind. Keep looking for a cheap 350. Ask your friends. Ask your frenemies. Ask your enemies. Somebody has one that they're tired of tripping over.

 

[tpass]

If you're short on cash, spending what little you do have to upgrade a 305 is peeing in the wind. Keep looking for a cheap 350. Ask your friends. Ask your frenemies. Ask your enemies. Somebody has one that they're tired of tripping over.

so true... i have 2 taking up 1/4 of my garage and they put evil thoughts in my head (like looking for another project car/truck)

 

[jd33173]

I have a 305 and was looking to do the headers and exhaust (which is completely hammered). My engine looks to be "vintage" and am thinking it would be a pita due to the old exhaust bolts possibly forcing machine shop activity. At the end of the day, even all fixed up, it would still be a 305. Right now I am looking to buy a dudes truck that got hammered but engine runs good. Have not seen the truck yet but Supposedly a 350. If i can verify, As soon as i can, i will be ripping that puppy out, getting it gone through and swapping for the 350. Your situation may be diffeent as your recently replaced engine is no doubt in better shape than mine but maybe work on some of the ancillary systems on your rig until the right opportunity presents itself. I am doing that until the engine situation gets resolved one way or another.

 

[RichLo]

Any Exhaust/intake upgrades yo udo to the 305 can be swapped over to a 350/383 in the future. Go with headers, free flowing exhaust. Worst case is you want more power so you swap in a 350/383 in the future, best case is its just perfect for what you need it for and you'll have a nice sounding 305.

 

[l1lartur0]

Anyone have thoughts/experiences with Hooker manifolds or ram horn manifolds?

 

[99xcss4]

Anyone have thoughts/experiences with Hooker manifolds or ram horn manifolds?

never used either but I like them both if headers are not an option