i blew up my SBC 350...thinking LS

[nabeshin]

A classic SBC with one of those port fuel injection manifold systems would give you the simplicity of old but reliability of a modern engine.

I'd do this before LS swapping into a classic vehicle.

 

[colonel mustard]

$1500 to rebuild your current 350 to make 375 hp? Power is in the cylinder heads, and unless you have some modern heads, even 300 hp is a stretch. And if your heads are stock, then 10:1 compression with the old style combustion chambers will make for lots of pre-ignition on regular gas, and maybe even today's premium. If you drive off-road, wouldn't you want lots of torque at low-mid RPM? A 350 with 375 hp is gonna like to be revved, and will be a little flat below 2500 RPM.

Cheapest way to make more power is cubic inches, so you should consider a 383, as mentioned above. Parts cost no more than 350 parts, unless those 350 parts are low-cost rebuilder specials.

Not trying to be nasty here, just realistic. Hope you end up with what you want, and not a 350 with a hot cam that sucks gas, has low vacuum, and won't idle consistently.

Thanks for the insight. I will ask him about a 383. My friend has one that was built by him 15 years ago and is still going strong.
I briefly considered a 383. Are they any less durable than a well built 350?
I drive the truck at highway speed often ....at this point. Has turned into lots of an overland”ish” truck. Minus the roof racks and shovels and ****.


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[colonel mustard]

Ain't that the truth!

This was my concern. I would want to do that swap right. And start with a motor with low mileage. Wanna guess what that costs?? Exactly....I lost interest when pricing it out the right way.



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[77 K20]

Thanks for the insight. I will ask him about a 383. My friend has one that was built by him 15 years ago and is still going strong.
I briefly considered a 383. Are they any less durable than a well built 350?
I drive the truck at highway speed often ....at this point. Has turned into lots of an overland”ish” truck. Minus the roof racks and shovels and ****.


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I replaced my 400 with a 383. The long stroke from the 400 is retained with the added benefit of having extra water jackets between the cylinders.

Only "disadvantage" over a regular 350 is they don't like to rev up as high. For driving off road at a low RPM I think it is perfect. My highway RPM is 3000 and is fine with that.

 

[1987 GMC Jimmy]

Yes, there are already plenty of half-assed hack jobs out there on vehicles with standard stuff, like small blocks with 4-speeds, TH350s, or especially 700R4s. Can't imagine how bad the LS/4L80E swaps would be.

I think some of the guys here are anal (like me) and have done stellar LS swaps, but they are in the minority.

As for all of the engines, even the 4.8 and 5.3, being called "LS", that's like saying a 305 is 350-based. If I ever did an LS conversion, I would start with an LS6 or LS2 to get the most bang for the effort. I don't know how a 5.3 would perform in a square, but it was sluggish in a 2011 Chevy pickup I test drove. Ended up buying a 2011 F150 with a 5.0 DOHC engine which had more horsepower than the GM 5.3, and felt like a 6.0 in comparison.

Definitely. A good chunk of forum membership is new owners being overwhelmed by all kinds of hack work being done to OEM power teams and control equipment and then needing to come here to help diagnose and troubleshoot.

I recognize the people that do it well, and being anal is imperative. If LS swaps were a niche thing, they’d probably still be doing it, and that’s cool. For some, the vehicle is the canvas, and the plant is the paint/brush. Then you get the whole bandwagon effect, and the well quickly becomes poisoned.

 

[colonel mustard]

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[nabeshin]

So yours rebuilt or a different engine?

 

[Bextreme04]

Still gonna buy the $700 Suburban? A quick part out would yield at least around $1000 in my neck of the woods, the scrap the rest. Put the cash towards your rebuild.

This is what I'm doing. I need to get a build thread going for mine, but I bought a running, driving 1997 K2500 Suburban for $500. It had the L29 MPFI 454 and 4L80E. I've gotten about $600 out of parting out the things I didn't want and basically got the engine, wiring harness, fuel system, drive shafts, and lots of other miscellaneous parts I will need for the swap for free. My truck is an 80' K25 350/TH400/NP205, so the 205 will swap over to the 4L80 with minimal extra work. The motor and trans had 288,000 miles on it and still ran and drove great. When I tore it apart is had definitely never been rebuilt and everything still looks in pretty good shape. Heads are out getting reworked and 454HO springs put in. Engine parts are going to the machine shop for cleaning and inspection today. Cam got send out to Delta Cams for a regrind to a MUCH better profile. I'll rebuild the Trans and NP205 myself and do all the wiring myself too. The biggest part with a retro-mod like this is to document everything. Later on down the road it becomes really hard to repair, replace, or troubleshoot any problems when you have no idea what is actually there.

I'm currently a mechanical engineer in the aerospace industry and have lots of professional mechanic and field service experience, so I have plenty of experience with wiring and manuals. I have the tools and experience to properly design the electrical system and draw the diagrams. I have a book that I started when I bought the truck and have been keeping track of what I've done and where the various parts have come from. It all adds up fast.

 

[colonel mustard]

So yours rebuilt or a different engine?

Rebuilt


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[colonel mustard]

This should help my left leg lol

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[1987 GMC Jimmy]

Saw a 4.3 to 5.3 swapped ‘85 earlier today for sale. Guy wants 23K, I think. Not terrible and carved, but I can see there were liberties taken with the swap after a <5 minute inspection. Some things change, but others stay the same.

 

[NastyRay]

X20 I’m running bbc 454 in my k30