Pondering a 305 rebuild vs. LSx Swap

[KMK454]

I bought my 78 about 5 years ago with 18k miles on it. I say it's all original but the reality is it's had some replacement parts here and there, some of the paint was poorly redone by the first owner, the emissions equipment is missing, and the exhaust from manifold back is not factory. Currently it has about 36k miles on it and I drive it almost every day.

As I've been replacing and fixing things on it to keep it roadworthy, I have yet to do any intense engine work aside from seals/plugs/wires/fluids and a carb rebuild. It runs very well but will need a rebuild sooner than later to run just right. But instead of putting all that effort into rebuilding the 305, I was pondering doing the following:

LSx (either an LS2 or LS3)
4L60E (would prefer manual but do not want to cut floorboard)
Any other parts needed to get the LSx setup running (wiring, fuel system, etc.)

The only exterior change would be widened factory rear wheels that would still sport hubcaps and whitewalls, so it would kind of be a "sleeper" except for the exhaust note.

Do LSx swaps require cutting or modification of the frame and/or body work? If I go through with this I want it to be as reversible as possible, with the stock 305 put in a crate.

The truck would lose that original look under the hood, but I predict it would get great gas mileage and the "character" that comes along with an old carb'd engine would go away. Thoughts?

Here's how it sits now:

[92GMCDriver]

i would do the lsx swap, building a 305 is just money down the drain. if you wanted to keep the small block and stay original i would at least get a 350, the heads that are available for the 305 are just awful and really choke them out. I do believe that there is some fabrication involved with the lsx swap such as motor mounts and such but ive never done one before. i agree that the engine compartment would lose its character because you just cant beat that old school look, but i think the gas mileage and raw lsx power is a good trade off.

[77BBGMC]

If you're not worried about keeping it original go with newer technology. For a daily driver LS motors are tough to beat.

I have to say that is a clean looking pickup. My GMC came new with that style of wheel cover. They've since dissapeared, I was watching for a straight set to add a set of whitewalls to and forgot about them until seeing your pickup, they look good.
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[Warrens69GMC]

350 short block L31
http://www.summitracing.com/parts/NAL-12556121/

Comp Cam
http://www.summitracing.com/parts/CCA-08-411-8/

350 aluminum heads
http://cgi.ebay.com/ebaymotors/SBC-C...item20bc01ce04

[my4by2]

First off let me say that I cannot come up with ANY reason to bother with the expense & hassle of rebuilding a paltry 305... They were NEVER a good engine to begin with & you really can't get much out of them regardless of what you do!

If you're looking to remain with the "old school" technology & a carburetor, then at the very least get you a good 350 core to build or better yet a good 350 crate engine (GM sells them for between $1,200 & $1,500) - maybe even a 383 for the added torque!

My vote however goes for the LS swap - you just can't lose with it!!! You'll get better mileage & overall power than you ever will with an older 350! You can do a swap with an original engine out of a wrecked truck - just make sure to get the pedal, ECM, harness & other parts. Then there's the aftermarket - I started with a low mileage used engine, but ended up getting an entire 6.0L package from Mast Motorsports because I wanted a "little more".

If you do end up swapping to an LS, take a look at Street & Performance for the headers - I am pretty happy with mine overall & they make them custom for a lot of LS swap applications.

Good luck in whatever direction you go in!

[STOCKISH]

There is an entire section of the board dedicated to this in the engine sub forum. Myself and about 200 other people have done the swap and there is more info in there than you can read in a day. Including part numbers, prices, and the like. Check it out. Good luck man.

[Mr. 250r]

In case your wondering about ls costs and all that just wait around for the deals I went from waiting on a 00 5.3 with everything for 1k to an 06 6.0 with everything for 1100 which around here is basically a steal as for mounts im going with dirty dingo here's there link http://dirtydingo.com/store/American...ngrutk4a3r1cc3
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[N2TRUX]

Do the LSx and you won't regret it. There was a time that I had the same mindset as you do. My truck was nicely restored and I wanted to retain as much of the originality as possible. Then I was determined to make changes that could be reversed if I ever wanted to. I finally realized that I was never going to take it back to original, and if I did it would probably have less value than it does as it sits now.

I did the 350 Ramjet in mine because I was already doing an LS motor in my Blazer. I wanted something good looking yet different. If I were to do it again, I would probably do a 6.2 instead. I have no regrets about the changes I have made, and I am looking forward to doing more.

[KMK454]

Originally Posted by my4by2

First off let me say that I cannot come up with ANY reason to bother with the expense & hassle of rebuilding a paltry 305... They were NEVER a good engine to begin with & you really can't get much out of them regardless of what you do!

Rebuilding the 305 wouldn't be so much of a "performance" build as it would be a restoration of my bone-stock mill. Since it's in pretty decent shape and all the parts are there, the price of having a basic resto/rebuild on it would be relatively cheap. But at the end of the day it would still be that "paltry 305" and if the motor's coming out for the rebuild, there's that opportunity for an LSx...

Originally Posted by N2TRUX

Do the LSx and you won't regret it. There was a time that I had the same mindset as you do. My truck was nicely restored and I wanted to retain as much of the originality as possible. Then I was determined to make changes that could be reversed if I ever wanted to. I finally realized that I was never going to take it back to original, and if I did it would probably have less value than it does as it sits now.

I did the 350 Ramjet in mine because I was already doing an LS motor in my Blazer. I wanted something good looking yet different. If I were to do it again, I would probably do a 6.2 instead. I have no regrets about the changes I have made, and I am looking forward to doing more.

Yeah, now that I've decided to keep the truck for life (unless something crazy happens), I'm more open to changing it. The thing is I love the original look, so I want to maintain the outward appearance, but I'd love a modern drivetrain in it. I'm just not into cutting/chopping frames and body panels, though... but the thought of a big tall 6-speed shifter mated to an LS3 in my truck makes me think otherwise about a hole in the floorboard!

The key would be to make it look like a factory sleeper, where nobody knew until the hood popped open.

[slammedLT1]

Quick and easy : 350 4bolt dressed like it was from the factory. painless!
Best approach: LSx engine!!
Worst idea: a 305 rebuild!

Just a personal opinion for your pondering! Put up a poll and see what wins

[smashingchuck]

Originally Posted by slammedLT1

Quick and easy : 350 4bolt dressed like it was from the factory. painless!
Best approach: LSx engine!!
Worst idea: a 305 rebuild!

exactly.

put the ls in it.

[slammedLT1]

like smashingchuck and dazed and confused have both said...

itd be cooler if you did!