427 build

[Pvmt-Pndr]

I just bought a 1969 C60 over the weekend. It has a 427 TD. This trucks fully intended purpose is to pull. I drove it 4 hours home at a top speed of 56 on the flats and 58 on the down hill... it was a 2 and a half hour drive in anything else.

She was making all kinds of noises I didn't like. Nothing that I believe requires a complete overhaul but may as well see what my options are. It definatly will be getting an OD transmission at some point for sure!

Currently it's a gutless wonder in what in guessing is a 10k pound truck. I was thinking of striking it to a 496 since it's easy and fairly cheap to do. This truck is a torque monster and power down low is fantastic! The problem is mid and top end power leaves a lot to be desired. If I go to a 496 I'll be able to rev it higher then it can now a max of around 4k rpm is what I've been reading. The tach is broke so I don't know exactly what I was spinning.

Keep in mind I want this for pulling not for going fast. 99% of threads I've come across is guys wanting to go crazy with the 427 TD and making tons of power. I don't need that. The other 1% are useless. I want to be able to spin it a little faster with more mid and top end power. Power down low in the rpm can be made up by the gearing it has in It, currently a 5 speed 1:1 5th gear ratio and a 2 speed rear end. I don't know what heads it has on it but I will find out, I would prefer to massage the current ones vs buying a new set. Price needs to be kept in mind since every single thing on the truck needs some love to be a reliable streetable tow pig.

[Tom]

The rpm limit is based on the giant 4 ring pistons and small cam.
Put normal 427 pistons and a new cam in and it will rev out fine, the shorter stroke means it can rev higher then a 454 or 496.
Not sure what pistons or stroker kits are available for the tall deck though. I'd go threw the entire thing first and make sure its not timing and carb related issues taking power out.

[Pvmt-Pndr]

I guess putting 427 pistons in it never even crossed my mind. For some reason I thought I remembered reading that it fits the standard 454 pistons. I'm not sure if that's correct or not. I figured if I was going to tear into it may as well go ahead and do it once with the 6.385" rods I think it was and a 4.25" crank. Flat top pistons most likely. As far as cam maybe something like an RV cam. I'm no expert here on any of this or gas engines much at all I've just been doing A LOT of reading not knowing what is facts or theory on what I'm reading.

Confirmed. The 427 and 454 have the same bore

[Pvmt-Pndr]

Putting 427/454 pistons from what I've been reading into an otherwise stock 427 bottom end makes no sense. Since the wrist pins are at a different height on the on the 4 ring design vs the 3 ring design. I would loose ci and all of my compression. I would have to get longer rods unless I want to have a custom set of pistons made, which I wouldn't. A new set of longer rods and new pistons would be the way to go at a minimum.

Currently the teeth are too far gone on the flywheel ring gear for me to do a proper compression test on the engine. Getting that fixed will be the first thing I will do. Any ideas around about what I should see as far as psi goes on a good tall deck? I haven't sound any solid numbers on that yet

[kwmech]

Find a spicer 6231 auxillary trans and call it good. You'll need the overdrive anyways. The 427td is a brute with torque if you keep the rpm where it is happy. I think redline on that engine is about 4200.

[Pvmt-Pndr]

Some of the prices I've come across looking for one of those would easily justify getting an nv4500 for it. Worse case would be to rebuild the 427 and get the nv4500. I'm sure I'd gain power just making the engine fresh again 80k or so miles on it before the odometer stopped working and would gain an OD with the new trans.

I'm trying to come up with a fezable and logical plan.

Dream plan would be to just drop a Cummins with the G56 into it. Those don't go for fezable or logical though.

[hans2]

You're not going to get more RPM/high end power out of that TD without dropping serious coin on it. To many factors at play keeping it limited to 4K and under. Take advantage of that low-end torque it was built to produce and either add an auxillary overdrive or swap in a 2-speed rear with a highway set.

Or simply learn to live with the speed limitation and appreciate the truck for what it is. These rigs weren't meant to be Sunday drivers or turnpike cruisers. Your assertion that a 4 hour drive in this at 56mph would be covered in 2.5 hours in "anything else" means that your "anything else" runs at 89.6 mph.

I don't think so.

You're clearly frustrated with the top speed potential, but you did buy a 50 year old 1969 C60. There's been 50 years of improvements in medium duty trucks since then, and none of the newest models cruise at 89.6 mph.

I hope you can appreciate what you have for what it is, and enjoy your classic Chevy.

[Pvmt-Pndr]

I'm not looking for a rocket. The more I read the more I have to agree with what you're saying. An OD trans will happen reguardless. I haven't looked into a different set of gears yet but will today and and see what the options are.

The 4 hour drive vs 2 and a half was because I was forced to take a completely different route because the expressway was not an option with the top speed of the truck. 89.6 mph is not what I'm looking for. 65 I would be happy with.

I do love this truck don't get me wrong. I loved every minute of that 4 hour ride home! I was surprised at how easy it is to drive also. The low rpm torque reminded me of driving a diesel. She was definatly happiest down low lugging.

[PGSigns]

Here is what we did with a 427 TD motor for a mud truck we had. This was not a high rpm skim across the top truck it was a see who can get to the other side of a deep a$$ hole. We took and bored it 30 and put a cheap set of .400 long rods in it and a set of decent 427 pistons in that gave us about 9 1/2 to 1. Had it re balanced. We cleaned up the bowls around the valves and did a good valve job on the 049 heads we had. Engine builder picked a rv/towing cam for lots of low end grunt. Topped it with a aluminum intake and a 650 holley. Motor just pulled and pulled. Sold that motor an couple of years later and it went into a C60 where it ran for years.
Jimmy

[hans2]

Roger that about the route difference. I just saw the pics of your new truck on the Heavy Haulers thread, looks like a real fine ride. I agree an OD trans would go a long way to making it more highway friendly.

PSG - do you remember which aluminum intake you used, and did you use a set of intake spacers?

[Pvmt-Pndr]

Thanks. It's a real nice truck for being 50 years old, no doubt about that! I'll be uploading more pictures here soon since it's kind of warm enough out

[Tom]

Originally Posted by hans2

and none of the newest models cruise at 89.6 mph.

You obviously live in a different area. Here in Phoenix, especially at rush hour, 80-90mph is the norm when your not sitting in bumper to bumper traffic. Its either full on or full off here traffic wise

[Mike C]

If I was pulling the motor out and going through it, the 496 is what I would do. I had a built tall deck 498” tall deck motor with an 8-71 Supercharger on it. I wound up selling it because a tall deck in a car is a GIANT PITA for exhaust. But in the C60 that was designed for it, go with it.

Maximum torque is based on displacement and compression ratio. The cam then just dictates at what point the numbers peak. So if you want pulling power, you want a bigger motor.

[hans2]

Originally Posted by Tom

You obviously live in a different area. Here in Phoenix, especially at rush hour, 80-90mph is the norm when your not sitting in bumper to bumper traffic. Its either full on or full off here traffic wise

You are right, I live on an island that has a max speed limit of 45 mph for just about half of its 12 miles of main road. Quite different than the rat race you describe. But I'm not sure that where I live, or where you live, has any bearing on the fact the current crop of medium duty trucks are not designed to cruise for 2.5 hours at 89.6 mph.

[Tom]

Originally Posted by hans2

the current crop of medium duty trucks are not designed to cruise for 2.5 hours at 89.6 mph.

No not quite, but we pushed many medium trucks to 75-80 for days on end in the moving company I used to work for. Semi's do it no problem at full load.

[Pvmt-Pndr]

So I've changed my plans for the engine as stated above. I bought a set of headers for it that will be going on since I need to replace the manifold gaskets anyways.


I'm going to regear the truck instead of doing a different trans or auxiliary trans.

I have a couple of questions though. Cam someone confirm that a 650 Holley would be a good option?

The ignition system is where I'm scratching my head. Once I get to the "higher" rpms she starts pinging like crazy! The previous owner installed a HEI distributor on it. As far as I know that's all he did. The vacuum advance is not hooked up at all. I feel like there is something I may be missing. I have not confirmed initial timing yet but will soon.