L31 build or older 350 , light to mild build? c10 truck

matt167 said:

Sell everything, and get a $500 LM7 Use the extra budget to get Holley Terminator X. You can get in the realm of 350hp on a stock engine with tuning and a set of headers. Camshaft can get you over 400hp. Want a little more power, swap on a set of 799 heads. Turbocharging can get you close to 1,000 hp without much thought... Depends on what a little more hp means to you..

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But know he’s back being tied to a friggin computer.

Kinda like the day I came home to find my wife and her friends took the Marantz system to Goodwill and put in a Sonos to surprise me. To say I was PO’ed is to put it mildly, but OK I tried to make love with it for about 3 or 4 years bought it presents to try and get it to play hard rock in my bones as well as my ears. So I’ve spent the past 3/4 year on Ebay reacquiring the old analog equipment the ole‘lady gave away. The price of this stuff keeps going up, it’s cost as much and some cases more to buy it used than it cost new. So I’m trying to figure out what’s going on? A little on-line research uncovers that I’m far from the only guy that is moving back to this older equipment. Now when I play Pink Floyd it’s like leaning over the exhaust of a double A dragster ya feel it in your bones.

Now I’m thinkin’ the old SBC is a lot like that Marantz, simple basic stuff that just gets the job done with carburetor and distributor without the need to digitize every simple thing. If really want a thousand horsepower buy a set of rollover heads and intake.



Bogie

Depends on which block your building.

The L31 Vortec block uses a factory roller cam, not that you can’t retro it to a flat tapped like the XE268H from Comp or another brand of similar timing and lift but the whole point of a street roller is to escape the wear problems of flat tapped cams so going to a flat tapped cam is not recommended when escaping it’s problems is so easy with a factory roller block.

You older flat tapped block would make the XE268H a good choice for the power and torque you’re looking for.

When it comes to roller cams the makers quickly add lift as this is something roller cams are good at. But cam performance in not simply duration as added lift also encourages the bad habits that are common with a longer durations and shorter LSA’s. So going back to the L31 block the equivalent duration to the F/T XE268H in a roller cam in the XE series would be Comp part number CCA08-423-8 but because of its lift you get into stall converter and choppy idle which the XE268H is just under that threshold. So if stock converter stall is to be retained and a aggressive but not choppy idle is desired then stepping back to the characteristics of the Comp CCA08-422-8 would be roughly the same as the flat tapped XE268H.

Bogie

I Think the l31 is the best bang for the buck.
G.m. own 350 ramjet is based off if it.
Change out the l31 cam and springs, (comp beehive and small retainers, g.m. ramget cam or same spec cm, and 1.6 ratio rockers and you have the ramget crate engine less the efi. it will make 330hp all day with a carb and headers.
The idea of dropping an LS based engine is great, problem is everyone forgets the true cost of that swap.
The different mounts, the bell housing adapter and converter spacer, starter, wiring, fuel system changes, (electric pump and wiring, return line) Adding the return line to the fuel tank, Getting the 1984 c-10 dash gauges to work on the swap. As the LS the computer drives the gauges. Different hoses, fan shroud mounting if engine driven fan, if electric fans that wiring, Ac compressor mounting on truck ls engines that may not clear the c-10 engine crossmember. without notching it. or going without a/c. new a/c lines, custom throttle cable and th350 kick down cable mounting and cables, or th400 kick down switch mounting. Assuming his 84 c-10 doesn't have a 7004r with a t.v. cable that opens another can of worms.
The 500 dollar ls swap is a nice daydream. And as long as you are aware of all the cost and work to make it happen, it is a good option. But easy and cheap it is not.
Low miles 85k-120k 5.3's with harness and ecu are 800-1200. 00 .
Last time I bought one to replace the one in a fleet truck. it was 950.00 with no harness or ecu. Maybe the 500.00 ls are out there but we have to buy from yards that stand behind what they sell, So we don't swap in junk and end up doing it twice.
If the Thread author is up for the swap, great, but I would say to him research what is truely required to make it happen and it's cost. Tons of ls have been swapped into Chevy and GMC square body trucks.
If I was to do that swap and Assuming this truck is 2wd ( he stated c-10 not k-10 so assuming 2wd)
I'd get a 5.3 with harness and ecu and the transmission that is bolted to it, the drive shaft and transmission mount/crossmember. Figure 2500.00 for it all. Then add all the parts to mount it in his 84 and plumed and wired.

Not sure where $800-1,000 5.3's are, but my local yard has 3 low mile DBC 5.3's for $450 a pop with their guarantee, and there is a local guy who parts out the trucks and will sell you an engine he can fire up for you for $500 and include an un cut harness. High mile engines are better for boost but are also cheaper. If your paying $800-1,000 and not getting a 6.0L your cheating yourself. You could add in Holley Terminator X and be in for around $2000. People do it every day.. Also running a 4L60E isn't really a good idea. Once you wake a 5.3L up and remove the torque management from the system and any little bit of power adder, a 4L60E is on life support. Adding senders for the original gauges is trivial. L31 is a great engine, but your going to find pooched out high mile junkers these days. They don't age like the LS engines and there are now less of them to go around. They only existed from 1996-2003. Keep your costs relative and you can get more out of an LS. Walking in a U pull it, any 2003+ Tahoe or Suburban has a 5.3L.

2014+ LT engines are where even more power sits, but a basic LT 5.3L will set you back $3k

But OP does not want an LS.

matt167 said:

Not sure where $800-1,000 5.3's are, but my local yard has 3 low mile DBC 5.3's for $450 a pop with their guarantee, and there is a local guy who parts out the trucks and will sell you an engine he can fire up for you for $500 and include an un cut harness. High mile engines are better for boost but are also cheaper. If your paying $800-1,000 and not getting a 6.0L your cheating yourself. You could add in Holley Terminator X and be in for around $2000. People do it every day.. Also running a 4L60E isn't really a good idea. Once you wake a 5.3L up and remove the torque management from the system and any little bit of power adder, a 4L60E is on life support. Adding senders for the original gauges is trivial. L31 is a great engine, but your going to find pooched out high mile junkers these days. They don't age like the LS engines and there are now less of them to go around. They only existed from 1996-2003. Keep your costs relative and you can get more out of an LS. Walking in a U pull it, any 2003+ Tahoe or Suburban has a 5.3L.

2014+ LT engines are where even more power sits, but a basic LT 5.3L will set you back $3k

But OP does not want an LS.

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It seems the junkyard pull outs of the ls, pricing depends on location.
ALSO, Some yards "guarantee" isn't worth the ink to type it . To a shop a "guarantee" that is nothing more than if it has issues well, give you another, but you foot the labor time to do it twice, is worthless.
Like I stated in the other post, I'm sure there are 5.3 ls out there for 500 bones. Depends on what and if you value your time and the roll of the dice that it is a good unit.
We have finished a few of these swaps that the vehicle owner started .
If I was the thread author and was to entertain doing the ls swap. I'd do my own research on what it has cost others that have dropped one in their square body truck, and the honest cost of all the things requires beyond the take out unit.
Including the making the truck ls a/c compressor location work in the 73-87 gm trucks.
To the DIY guy that can risk the engine not being what the yard or person said it is. I am not here to tell them not to go for it. I stated in my other post that ,shops and folks getting paid to replace engines can not afford to do it twice. Job time promised,labor cost, comebacks are reasons we get parts/units from one yard and not a few of the others.
The thread author said he is on a budget. What that is, is for him to know, And why I would advise he do the research on what it takes from others that have done the swap in his type truck.
The true beauty of the ls engine is the number of good strong running gen 1 350 Chevy small blocks out there for sale complete for 150-200 bucks, that were pulled out because the person wanted the ls engine.
They maybe out dated and old tech. but If all you need is a strong solid engine. That is stone age simple, you can not beat it.
Most of the truck Vortec 350's trucks are in yards because of the pop it valve spider central efi, the long block is just fine, or the 4l60e(7004r) gave up the ghost.
Another issue with the take out ls that everyone glosses over is the o.e.m. ecu is looking for a bunch of sensor input data and module input data, That are not installed on/in the vehicle you swapped the ls into, setting off the SEL light (check engine light) . So now you need a buddy with a tuner that knows how to delete the inputs you did not install that the donor vehicle had.
It is not as simple and easy as may make it out to be, at least if you install one correctly and don't have the ecu pulling power because the SEL light is on, or would be if you installed it.
Many folks are making silly power on junkyard 4.8 ls and a ebay turbo.
like most things in this hobby, it depends on skill and budget.
I wish the thread author best of luck with whatever route he picks. best way to not not have surprises in the middle of an engine family swap is to pick the brains of those that have done it to the same vehicle.