489ci tow build...

[Catbox]

My guy.
What are the current specs of the 454 in your truck?
Everybody skipped that part of the process.

 

[Grit dog]

To build a big, big block for towing, the only goal has to be smiles per gallon. Must be low miles towing or you could spend the whole build budget just on extra gas in a short time.
Honestly, I’d want to just 12v or 24v it if I was packing on the miles at all, but in your case that would require either taller gears or overdrive because the big C would be wrapped and tapped at 69mph!

 

[Catbox]

The 454 that was mostly stock in my '79 would barely turn its own tire over with me dumping the clutch.

Enter some simple to do mods and it is a totally different engine and far more powerful.
The engine in the truck was replaced with a factory rebuild in 1990.

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Total 100% stock old feller snooze fest here...

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It has over a hundred more cubes than the 350 in my 1995 Suburban and probably was choked down to the same dismal power output the Sub has.
When it has a big block in it and makes 200hp, it is just sad.


Enter me with the budget build of the stocker using swap meet sourced parts on the engine.
A simple Edelbrock Performer 2.0 intake that is made for the little peanut port heads.
Topped with a Holley 750 vacuum secondary carb that was rebuilt by my 19 year old kid at the time.
The headers were free from a buddy that replaced them with coated ones.
The headers by the way are made for 1968-1972 Nova and fit like champs with very little extra beating on them needed.
Follow those up with a free flowing 2.5 inch exhaust with Flowmaster 40 series mufflers and the truck is a beast.
We found an MSD module in a junkyard truck that makes the spark that much nicer to run through the swap meet set of MSD 8.8 wires.
The air cleaner was from the swap as well and that includes the K&N filter.
I might have $600 in cost to put all this stuff on the engine.

Here is an in process shot, as the fuel line is bluetooth at this point.

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Those Nova headers tuck up in the frame real well too.
The front crossmember hangs lower than any part of them.

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Could it be better, totally.
Is it far beyond better than it was when it was stock, absolutely.
We did nothing to the inside of the engine to this point.

It is so much better now, my son made sure these tires were not good for anything before we put the new ones on it.

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[Marmstrong95]

You say you know LS engines... Have you considered the 8.1L big block? You can get a complete truck for $1500 if you're lucky. It will bolt to the TH400 and still has the bosses on the block for traditional SBC/BBC mounts like your truck. You can use your stock exhaust manifolds or get headers that fit your truck, but it is a tall deck motor so it won't line up with stock exhaust. Throw a vortec pump on your stock sending unit and you're there.

More cubes, fuel injection, cool factor...

 

[Catbox]

I may opt to install a spare set of the L-29 Vortec heads onto this engine before we retire it from service.
Here is a photo showing the 100cc chamber of the Vortec that is much smaller than the 119cc of the peanut port.
Bolting these on should bump the compression up a full point from the stock 8.0:1 to a healthier 9.0:1.
The internet dyno nerds say it is a 30 to 40 horsepower bump.

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From the research I have done, these are the gaskets to do the head swap as they have the correct holes in the proper places to marry the Gen 4 block to the Gen 6 heads.
I would check my work before you spend your hard earned money on my rantings.

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But I also have a complete L-29 engine that may just get swapped into the truck.
I will rebuild it eventually and when I do, the stock cam is getting removed and reground or tossed in favor of a better grind.
Also note the attached 4L80 transmission that will be installed in the truck at the same time.

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I want one of the cams that came in a ZZ502 engine as just installing that into the "stock" engine is supposed to get you around 450hp and 500ft/lbs.
If I cannot source one of those, something like this will be put in place.

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[bucket]

I may opt to install a spare set of the L-29 Vortec heads onto this engine before we retire it from service.
Here is a photo showing the 100cc chamber of the Vortec that is much smaller than the 119cc of the peanut port.
Bolting these on should bump the compression up a full point from the stock 8.0:1 to a healthier 9.0:1.
The internet dyno nerds say it is a 30 to 40 horsepower bump.

You must be registered for see images attach

From the research I have done, these are the gaskets to do the head swap as they have the correct holes in the proper places to marry the Gen 4 block to the Gen 6 heads.
I would check my work before you spend your hard earned money on my rantings.

You must be registered for see images attach

But I also have a complete L-29 engine that may just get swapped into the truck.
I will rebuild it eventually and when I do, the stock cam is getting removed and reground or tossed in favor of a better grind.
Also note the attached 4L80 transmission that will be installed in the truck at the same time.

You must be registered for see images attach

I want one of the cams that came in a ZZ502 engine as just installing that into the "stock" engine is supposed to get you around 450hp and 500ft/lbs.
If I cannot source one of those, something like this will be put in place.

You must be registered for see images attach

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Here's the Vortec heads side by side with the lowly peanut port heads:

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[Z28 Guy]

Specs on my 454 is that it is bone stock engine for the 87 model R20. I think its rated at 240hp/330TQ which is weak for a 454 ci motor.

I have thought about a 8.1 swap however the aftermarket for them are very slim. Plud the 8.1 parts are really high dollar.

I have thought about a L29 swap myself but from research tells me people try to hold on to them.

Positive note is that im go build on paper before buying anything. Careful planning and parts selection makes or breaks a combo.

 

[Catbox]

Do the simple things to yours as I have done to mine.
It will behave like a different truck.
Even with the little tiny cam that is in it.

Another thing on the L-29 vs PP heads.
The L-29s have a 235cc intake port where the PPs are 200.

 

[Bextreme04]

I am swapping my 350/TH400 for an L29/4L80. I just bought an entire 1997 K2500 Suburban that had the interior and suspension trashed for $500. Engine/trans started up and ran good enough to drive it home. I rebuilt the engine and trans with all new components for ~$3000 including bigger injectors, regrind of the cam, adjustable valvetrain components, 24x crank reluctor, and 0411 ECU conversion. It got mostly completed about 2 years ago and then sat on the back burner in my shop since then while I completed other things. I just finally got what I hope are the last little details ironed out yesterday and am final running the wiring harness on the engine/trans this week and hope to swap everything out this weekend. The 24x reluctor lets me get rid of the vortec spider distributor cap and run LS3 individual coil packs. I bought a set of Moroso bracket mounts that they developed for the GM 572 crate motor and they really give a good a good clean solution for the coil mounting.

Cammed and tuned L29 will usually be somewhere in the 350-400hp range(at the crank) and 400-500lb-ft of torque(at the crank). The factory L29 intake is a huge limiting factor and is really designed for low end torque and runs out of air above ~5000RPM. My regrind on the factory cam should be similar to a GM 454HO crate motor. I had the heads redone and set up with factory 454HO valve springs and rotator eliminators too. The GM 454HO is a Gen VI block with slightly better flowing rectangle port Iron heads. That, combined with the dual plane intake really lets it breath better than the L29, but sacrifices some low end torque. If you were to take an L29 and run the 454HO or ZZ502 cam with a dual plane intake and a decent carb... it will be a night and day difference to a factory 70-80's 454.

 

[Z28 Guy]

well that sounds like interesting build. Im taking notes and learning daily for sure. I never knew you could run LS coil packs on a L29 with some tweaks. Thats awesome. Keep me posted on how your builds turn out.

Speaking of notes i want to share these with yall and want opinions.

 

[Bextreme04]

well that sounds like interesting build. Im taking notes and learning daily for sure. I never knew you could run LS coil packs on a L29 with some tweaks. Thats awesome. Keep me posted on how your builds turn out.

Speaking of notes i want to share these with yall and want opinions.

I would stay away from keith black pistons. By the time you acquire and rebuild any of those heads, you could have just bought better aftermarket ones. If you are going to put factory iron heads on anything, your best bet is to go to a junkyard or find an L29 locally and just get the block/heads as cores to start with. There are 2 or three of them on facebook marketplace right now locally to me for ~$400 asking price as just a parts core. I had the entire heads cleaned, inspected, guides replaced, valve job, and new springs installed on my stock L29 heads for ~$500. They flow better stock than even reworked 049 heads will and they will bump your compression ratio up to a reasonable number. You are going to want to be in the 9.0:1 or higher with iron heads. You can get an entire stroker rotating assembly, already balanced for under $2k. You can get a good set of AFR enforcer heads for another $1500-2k.

Best bang for buck would be to get a Gen VI block, the more complete the better. Have it bored .030" over. Run a cast balanced 489 stroker kit. Get yourself a good set of aluminum oval port heads. Call up Delta camshaft and tell them your setup, then send them the stock L29 roller cam core and have it reground custom for your setup. It was ~$140 to have this done for my setup and then you have a high quality factory billet cam core that is custom ground for what you want. You will need to measure your block and order a rotating kit that is going to give you a good quench and correct compression ratio for the chamber cc and shape of the heads you are going to use. Alternatively, have the factory L29 heads rebuilt. They will flow enough for ~600hp with a good cam and intake combo.

A stock Gen VI or Gen VII with a cam, dual plane intake and carb is going to make your numbers you are shooting for with literally nothing else done to them. A Gen VI with a stroker kit will make almost exactly the same numbers as the Gen VII. Here's a shootout with dyno numbers on stock Gen VI and Gen VII by Holdener with readily available cams.

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[Z28 Guy]

Bextreme~ i would love to see your build on paper or simply just laid out with all the specs on the cam etc.