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Trying to decide direction with first engine build

The_Tomato

The_Tomato

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Hey everyone,

Like the title says I'm trying to plan out and budget for an engine build for my '89 K5. I swapped in a stock-replacement gm crate back in early 2016, but I'm 5 years down the road. The Blazer is no longer my DD, I have a much better (but not unlimited) budget, and I have some time on my hands. Here's what my train of thought has been:

I'm running 33's, 3.73 gearing and a stock 700r4 on 2" of lift. I don't want some radical race motor that doesn't idle and calls for a high stall converter. I want my truck to be reasonable enough to let my folks borrow it for a weekend to the beach while being powerful enough to not have to floor it when I'm rolling up to the mountains to do some light wheeling. To me, that's maybe 325-350 at the crank with slightly higher torque numbers if possible. I'm not sure if I should just save up some cash, buy a running LM7 truck and steal the powertrain out of that or if I should rebuild the spare smallblock I have laying around and put an efi system on it. I did some tooling around with the search feature but I'd like to have my own thread for specific discussion.

Thanks!


tl;dr- I'm looking for engine build suggestions/direction for my '89 fullsize
 
Additional info- I'd like to begin this build this fall after I enjoy the summer. Budget is between $2000-2500 but has some flex and I can be patient to save up more if need be.
 
What crate is in it? Maybe a cam swap, EFI, and some exhaust work can fit that budget
 
Cam https://www.ebay.com/itm/COMP-CAMS-EXTREME-4x4-262-SBC-/170284198321

Top end kit https://www.summitracing.com/parts/cmb-08-0034/make/chevrolet

Distributor https://amzn.to/3loCxb9

Bearing kit https://smile.amazon.com/CLEVITE-Be...earing+kit&qid=1615921802&s=automotive&sr=1-1

Oil pump https://www.summitracing.com/parts/mel-m55hv

Pushrods https://www.summitracing.com/parts/cca-7812-16

Pistons https://www.summitracing.com/parts/sum-17350c-30

Rings https://www.summitracing.com/parts/slp-e-251k30

Things I can reuse-
block
valve covers
crank
oil pan
harmonic balancer

basically anything external on the block will be just fine with a bit of degreaser and enamel paint.

Definitely want to look into some headers, but I'd want some that are ceracoated and I'd be worried about thermal shock from mud puddles. Exhaust was done up to a 3" pre-cat and cat back 2" duals a few years back, but it's getting rusty and could probably use a rework. That wouldn't be included in the engine budget.
 
Two observations:
The pistons and bearings should be good right, only a few years old?

Check the valve lift limits on the heads spec’d in the Summit link. Vortec heads are notorious for valve issues, and more valve issues above .450” lift
 
Bent77 said:
Two observations:
The pistons and bearings should be good right, only a few years old?

Check the valve lift limits on the heads spec’d in the Summit link. Vortec heads are notorious for valve issues, and more valve issues above .450” lift
Click to expand...
The pistons and bearings currently in my truck are fine, but I'll be rebuilding the block I pulled out. That'll most likely need to be bored over and I think I want the bump in compression that the flat tops will give. That point about the lift limits is definitely one I need to look into though.
 
Look up the ZZ6 crate and check out what they are getting out of that engine at 9.76:1. That’s also the cam I would recommend if you can get some good heads. The SP350/385 is the same engine with a dual plane intake, slightly different RPM on the power curve. GM has a parts listing for those also if you’re interested
 
Bent77 said:
Look up the ZZ6 crate and check out what they are getting out of that engine at 9.76:1. That’s also the cam I would recommend if you can get some good heads. The SP350/385 is the same engine with a dual plane intake, slightly different RPM on the power curve. GM has a parts listing for those also if you’re interested
Click to expand...
Thanks, I'll use some of these parts as a reference!
 
Anymore I think the way to go is one of the larger displacement LS'. I wouldn't want a small one, it's the difference of using a big block vs. a small block. You don't need to hotrod a big block to feel the power difference between it and even a fairly stout small block, especially in a heavy, non-aerodynamic truck. If you want power, you are crippled out the gate with the 5.3. Not saying it's a bad motor, but is anyone gonna argue it's more powerful than a 6L, or that the 6L isn't going to have an easier time?

LS swaps are done by the millions, they are good engines and injection systems, and they make very good power even before modification.

I'd much rather have an engine that makes good power bone stock, than have a finicky thoroughbred for a vehicle that I didn't want issues with, didn't have super specific goals for, and I wanted others to be able to enjoy as well.
 
dyeager535 said:
Anymore I think the way to go is one of the larger displacement LS'. I wouldn't want a small one, it's the difference of using a big block vs. a small block. You don't need to hotrod a big block to feel the power difference between it and even a fairly stout small block, especially in a heavy, non-aerodynamic truck. If you want power, you are crippled out the gate with the 5.3. Not saying it's a bad motor, but is anyone gonna argue it's more powerful than a 6L, or that the 6L isn't going to have an easier time?

LS swaps are done by the millions, they are good engines and injection systems, and they make very good power even before modification.

I'd much rather have an engine that makes good power bone stock, than have a finicky thoroughbred for a vehicle that I didn't want issues with, didn't have super specific goals for, and I wanted others to be able to enjoy as well.
Click to expand...
I was talking to my buddy this evening and he was saying the same thing. I think I'll save up some more and try for a larger displacement LS swap or keep an eye out for a cheap junkyard big block to build. I'm more prone to the big block swap, but it will most likely come down to what i find first.
 
I'm biased, there won't be a carbed anything going into any of my vehicles that injection is an option on.

Aftermarket injection has gotten better, but as with my statement above comparing the 5.3 and 6L's, who is going to argue a bone-stock OEM LS doesn't run better than x, y, or z aftermarket injection in terms of overall drivability? Again, for what it sounds like your uses are, a "drop in", stock (but still good power) injected engine would seem to be ideal. Self learning EFI still isn't 100% as far as I can tell (still going to be fiddling with tuning under certain conditions) so IMO it's a bridge between a carb and factory injection.

If I'm not mistaken, there should be a couple somewhat common LS setups out there that are at least knocking on the door of the power levels you want, if not exceeding them.

Carbs can work too, and not be real problematic, but vs factory LS injection, lol. If I was expecting non-gearheads to drive my vehicle, I'd not want peculiarities in how it has to be driven. Most today are used to hopping into a vehicle, turning the key, and immediately driving off. Anything outside of that and people are lost lol.
 
I'm happy with the 5.3 L83 in my 77 K5. Would I have liked the 6L, of course, but I get 17-18 mpg running 4:10 gears and 37" tires and have not really needed more power. It's about as easy as it gets for turning the key and taking off.

Edit for transmission... still running a TH400
 
The_Tomato said:
Cam https://www.ebay.com/itm/COMP-CAMS-EXTREME-4x4-262-SBC-/170284198321

Top end kit https://www.summitracing.com/parts/cmb-08-0034/make/chevrolet

Distributor https://amzn.to/3loCxb9

Bearing kit https://smile.amazon.com/CLEVITE-Be...earing+kit&qid=1615921802&s=automotive&sr=1-1

Oil pump https://www.summitracing.com/parts/mel-m55hv

Pushrods https://www.summitracing.com/parts/cca-7812-16

Pistons https://www.summitracing.com/parts/sum-17350c-30

Rings https://www.summitracing.com/parts/slp-e-251k30

Things I can reuse-
block
valve covers
crank
oil pan
harmonic balancer

basically anything external on the block will be just fine with a bit of degreaser and enamel paint.

Definitely want to look into some headers, but I'd want some that are ceracoated and I'd be worried about thermal shock from mud puddles. Exhaust was done up to a 3" pre-cat and cat back 2" duals a few years back, but it's getting rusty and could probably use a rework. That wouldn't be included in the engine budget.
Click to expand...
x2 on the Comp Cam. I've got one in my 77 SBC 400 and it makes a ton of torque. Buy the kit and it includes the cam,, lifters, pushrods, timing chain, and sprockets. The whole shebang.
 
DB Cooper said:
I’d just rebuild your block into a 383. A mild build will easily get your power numbers and the torque is fun to drive.
Click to expand...
With my 400, I can roll on the throttle in any gear, and the old girl will get with it. I just don't get the mileage of a 5.3, but then a 5.3 doesn't have the torque of a 383 or a 400.
 
Having run a LM7 in my K5 with 35's and 4.10 gears with the 700r4 I will say to the OP that for the expense you go through you'll be disappointed.

5.3's just don't have enough low end torque without help of a turbski or blower. Most cams will drive the torque even higher. This fights against your less than optimal gearing with the tires you have. You will need to bump the gear ratio to keep the 5.3 in it's torque curve.

A 6.0 would be better obviously but everyone and their brothers want them too for the same reason and it's keeping the price inflated for even 200,000 mile dogs.

I've posted it before, but it bears repeating. Go look for a L29 Vortec 454. Good stock heads, roller camshaft and a reliable factory efi system. Guys trip over the L29's going after 6.0s and other LS based engines. You can buy complete trucks running with them for the price of what some want for a whored out 6.0. I picked one up for $750 and the guys tossed the 4L80e in for free because they didn't want it.

L29's bolt in and don't require adapter mounts like LS engines do. The rest of the efi system is similar to doing a LS swap. Get a standalone harness, tuned ecm and it's pretty easy to get into the truck and make it a runner.

Stock the L29 puts out 410 lb/ft at 3200rpm. The LQ4 puts out 360 lb/ft at 4000rpm. That's noticable by anybody mashing down on the loud pedal.

I would bet the LQ4 isn't going to be any better on fuel consumption given the fact you are going to rev it higher to get the power out of it.

Plus the L29 is a cam and spring swap away from 500+ lb/ft with a conservative tune. Still peaking at a lower rpm than the LS engine.

I've personally been involved with a local buddy that swapped an L29/4L80 combo into with 4.56 gears and 35" tires. It's a ripper. Gobs of torque down low. It's in a suburban with a full 2" tube exo-cage that all together weighs 6500 pounds with no extra gear onboard. It still gets with it when you hit the pedal.

Can't beat displacement if you want low end grunt.
 
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