1984 k20 sbc swapping to a 1973 454

[RobShook]

Hi swapping a 1973 454 into a 1984 k20 Camper/Plow Special. This truck has a sm465/np208 currently in it. I would like to keep this combo in. My question is what flywheel do I use for this year motor? I know there is different teeth count, but don't know what to go with. Only 30k on this motor. With only about 240hp I want to bump that up to 300 or so. It does have a Edelbrock Performer intake and I'll install Hedman long tube headers/w 2-1/2" exhaust. This truck will be carrying a slide in truck camper, so no hot rodding. Any suggestions will be greatly appreciated.

 

[legopnuematic]

I believe 454s only used 168 tooth ring gears. So a flywheel for a 1973 or 1984 should be the same.

 

[Ricko1966]

A cam swap would go a long way for more HP and Torque. But with a 30,000k motor I think I'd live with what it came with. I also think a factory quadrajet manifold would be a better choice fir a low rpm truck pulling the weight and drag of a camper.

 

[hack_man]

I asked Mr. AI what he thought about the Edelbrock performer intake vs factory and Ricko1966 is right, there is some loss at the low end. I put the Performer manifold in my '83 K10 305 engine but I also re-geared to 4:11's.

The Edelbrock Performer 454 Manifold utilizes a dual-plane, low-rise design engineered to optimize torque from off-idle to 5,500 RPM. Compared to a factory stock intake (like the classic cast-iron GM Quadrajet), the Performer broadens the mid-to-high RPM torque curve while offering significantly better flow and throttle response. [1, 2, 3, 4]

Key Torque Curve Differences

• Low-End Torque (1,000 to 3,000 RPM): The Edelbrock Performer and factory intake curve are largely neck-and-neck here, providing the immense, tire-roasting low-end punch a 454 c.i.d. motor is known for. However, the factory intake often peaks slightly lower down the RPM band (around 3,500 to 3,800 RPM). [1, 2]
• Mid-Range Power (3,000 to 4,500 RPM): This is where the Edelbrock pulls ahead. The Performer out-performs the factory manifold, frequently producing gains of 15 to 20 lb-ft of torque in the mid-range. It allows the engine to breathe much better as it approaches the upper rev limits. [1, 2]
• Top-End Power (4,500 to 5,500 RPM): Factory cast-iron manifolds restrict air at higher RPMs, causing the torque and horsepower curves to flatten and drop off quickly. The Edelbrock Performer keeps pulling cleanly up to 5,500 RPM. [1, 2, 3]

 

[RobShook]

My son and I have owned this engine for over 20 years. Originally bought out of a motor home with 27,000 on it. Picked up the intake and some MT valve covers at the Flea market for $100 in 2003 for it. OEM intake was damaged, so it had to go. We installed it as well as the t400 that was on it into a 60 Ford F100. Did alright. Wondering what cam to liven it up some what? Biggest thing is which flywheel to get since it is a earlier 73 year model. 153 tooth versus a 168 tooth. Have several starters but not sure if that makes a difference.

 

[Bextreme04]

My son and I have owned this engine for over 20 years. Originally bought out of a motor home with 27,000 on it. Picked up the intake and some MT valve covers at the Flea market for $100 in 2003 for it. OEM intake was damaged, so it had to go. We installed it as well as the t400 that was on it into a 60 Ford F100. Did alright. Wondering what cam to liven it up some what? Biggest thing is which flywheel to get since it is a earlier 73 year model. 153 tooth versus a 168 tooth. Have several starters but not sure if that makes a difference.

re-use the one off the 84? Or does the 84 currently have a 350? You just need a flywheel/clutch kit for any squarebody 454/SM465 combo. They should all have been the same as they were all Mark IV 454's for all years. Unfortunately, an early 70's 454 from a motorhome is going to be a pretty bad flowing head and a low compression ratio, so a cam is only going to do so much. If you don't want to get into the engine too much or drop the money for a roller upgrade, something like a comp Xtreme Energy XE-262H or similar would give you a pretty nice increase in power while keeping a drivable tow rig.
https://www.summitracing.com/parts/cca-cl11-238-3/make/chevrolet

 

[bucket]

The answer is always a proper (not stock) cam, as long as the budget alows for it. A large trailer is never pulled at 1500 rpm, especially if any sort of incline is involved. Much more time is spent at 2500-4500 rpm.

 

[bucket]

Oh, and just get a flywheel for any '73-'90 454 with a 168 tooth count. That's what is needed to fit with the current sm465.

 

[83K31003]

As said above by all means use a 168 tooth count large flywheel - any truck application needs the added weight and leverage of a heavier flywheel. The 153 tooth stuff is for passenger cars.

Peanut-port heads didn’t hit the scene until about 1975 - your ‘73 oval-port castings should/could be some of the better flowing ovals offered by GM in trucks of all chassis’s and/or passenger cars.

Stick with that Edlebrock manifold and put a decent cam in it ( the stock one is lame at best ) and enjoy the mild power of bigger cubic inches.

 

[bucket]

The peanut ports actually didn't come until much later even. 1979 I think.

If they are the 781's or 049's, they are a great head to use.

 

[83K31003]

The peanut ports actually didn't come until much later even. 1979 I think.

If they are the 781's or 049's, they are a great head to use.

Didn’t know the the P/P heads came in that late - always learning something.

049’s or 781’s ( and a proper wiggle-stick ) are just what a truck 454 needs to run well at almost any RPM power range - he’s gonna like it.

 

[idahovette]

049s and 781s work REALLY good when you add the 2.19 intakes and the 1.88 exhausts

 

[RobShook]

Thanks for all the input. I think a cam is in the budget to wake her up some. Jegs suggested a 153 tooth flywheel. It is one of those low hp motors, but with only 30k on it kind of hard to do a lot to it. Got to find some AC brackets for it. Florida heat is a little too much for my old bones.

 

[Chugalugg]

I did this on my 84 K20, removed a 350 and installed a rebuilt '73 454. The first thing I found out is that the fuel pump on early 454's won't clear the frame as the 84 K20 didn't come with a big block. I used a shorter 396 pump. I had to change the fitting on power steering pump to the o-ring version. Several more obstacles and wish I would have stroked the 350.