Some Big Block help please.

[wanderinthru]

Getting my ducks in a row to change the 350 in the 75 for a big block. Not looking for a hot rod, contrary to that actually. Needing a smooth idle, with plenty of torque up to about 55/60 mph. It will have a wet kit, and has a 30,000 lb (ish) winch which will run via the hyd. Will also have hook ups in the back to raise, lower plows, and be able to transport them as well, we are talking 45 to 60 foot wide plows unfolded. As well as be able to drag my trailered back hoe, it's an old John Deere 410 D that weighs in around 15,000. In what I have been able to assertain seems a 427, with the correct cam and compression may be more ideal than a 454? Any and all thought, experience etc.. is appreciated. Believe it has 456 gears.....haven't checked yet, but it is pretty low.
Not doing an LS, or efi or anything with very many wire, going with the kiss approach (kiss= keep it simple stupid)

Thanks!

Shakey

 

[87scotty]

check out my 468 think ive got everything posted on there nice flat tq hp curves 500hpish 500ftlbs ush

 

[1987 GMC Jimmy]

If you can find an old P30 based camper, I’d yank the whole powertrain. Might be the way to go if you’re starting from a 350/350 combo. Those are generally low mileage, cheap to acquire, and if it passes a wet/dry compression test, there you go. You spend a little bit up front, and then you can work with your heads/cam/timing set, headers, intake, and keep the Quadrajet. I supposed head gaskets and dished vs flat-top pistons, in addition to the heads, would be worth considering if you needed more of a compression bump than you’d get with the standard bolt-ons (you’d be starting from an anemic 7.9:1 stock). The low end torque on these is there, and it probably wouldn’t need much to put it over the line. The Roadkill guys really brought along a Chrysler 440 with bolt-ons and doing nothing to the short block for the first iteration of their General Mayhem build. If you plan to drive it any significant amount empty sans your various PTO equipment, a 4L80E with a standalone controller might be a good upgrade to alleviate the realities of your gearing, and you can just tow in ‘D.’ Otherwise, the THM400 would be ideal if it will always have a plow or trailer in the picture.

 

[wanderinthru]

@1987 GMC Jimmy, thanks, Had never considered an rv for an engine.... do now. This old truck is a 4 speed manual.

 

[Turbo4whl]

Your 4 speed is what you need if you want a PTO on the 2 wheel drive C30. For an automatic you would need to step up to a medium duty Allison AT540 and big block. The K trucks, if automatics, with a 203 or 205 transfer-cases have a PTO provision.

 

[wanderinthru]

Your 4 speed is what you need if you want a PTO on the 2 wheel drive C30. For an automatic you would need to step up to a medium duty Allison AT540 and big block. The K trucks, if automatics, with a 203 or 205 transfer-cases have a PTO provision.

Yes sir, it is going to stay manual, has a driver side pto on it now, am looking for a passenger side one. have the hyd pump, so closer, lol.

 

[1987 GMC Jimmy]

@1987 GMC Jimmy, thanks, Had never considered an rv for an engine.... do now. This old truck is a 4 speed manual.

There you go! That SM will work just as well. And plus the RVs got an 800 CFM Quadrajet so it’s unlikely you could (or ever would) build the engine to the point where it would outgrow the carb.

 

[Mark Jones]

Internal balanced 4.280x4.00, long skirt metric ring pack piston, 8.5 comp, 6.385 long rod, 236 peanut port head with a 2.100/1.780 valves, of course high end machine work or it will not last. 7 quart truck pan with windage tray. 210 @ .050 hyd roller on a 111 installed 107.

 

[Big Chip]

Internal balanced 4.280x4.00, long skirt metric ring pack piston, 8.5 comp, 6.385 long rod, 236 peanut port head with a 2.100/1.780 valves, of course high end machine work or it will not last. 7 quart truck pan with windage tray. 210 @ .050 hyd roller on a 111 installed 107.

Are you Vortec Pro from Team Chevelle? If so you guys all need to listen to this man!

 

[BigDaddy72]

496 excellent for a tow rig.

 

[Catbox]

If starting from scratch, I would source a L-29 Vortec 454 from a junkyard.
It can utilize a great deal of the parts that are out there for big block chevy engine and has the added benefit of a roller cam.

I have one that I will be rebuilding and it has decent flowing heads for factory stockers.
It will also have flattop pistons and smaller chambers in the heads for a decent compression ratio.

Sourcing a camshaft for it is also pretty easy as there are many current options out there from mild to wild. Also like @Bextreme04 has told me, you can send the stock cam off to be reground to your application / specifications of intended use.

 

[Bextreme04]

If starting from scratch, I would source a L-29 Vortec 454 from a junkyard.
It can utilize a great deal of the parts that are out there for big block chevy engine and has the added benefit of a roller cam.

I have one that I will be rebuilding and it has decent flowing heads for factory stockers.
It will also have flattop pistons and smaller chambers in the heads for a decent compression ratio.

Sourcing a camshaft for it is also pretty easy as there are many current options out there from mild to wild. Also like @Bextreme04 has told me, you can send the stock cam off to be reground to your application / specifications of intended use.

The L29 was my choice for a couple reasons. It is 9.0:1 CR stock. The heads are actually REALLY good and flow great up to about 5k RPM, which is all you need for a truck/towing. The stock cam is garbage and the real limiting factor for the stock engine. It is still making over 300hp and 450 lb-ft of torque in stock trim. Just upgrading the cam to a chevrolet performance 454HO or ZZ502 cam wakes it right up and will get you at or near 400 hp and 500 lb-ft of torque reliably. Those cams are easily found anywhere and cost <$200. I had my stock one custom ground by Delta Camshaft in Tacoma, Washington for $140 shipped out the door. I bought an entire driving 1997 K2500 Suburban for $500 and stripped it for the drivetrain. I've sold about $800 worth of parts off of it that I won't be using and will probably get $100 more in scrap when I turn it in to the local metal recycling center. I just had the motor fully redone and it cost me ~$2000 for cleaning/hot tank, decked the block, bore&hone .020 over, new pistons and rings, balanced rotating assembly, new lifters and pushrods, new cam bearings, new water pump, new balancer, new oil pump, polished crank, and all the other new parts and gaskets to assemble the engine.

The L-29 is a factory 4-bolt main, hydraulic roller, Gen VI 454. It is the same base block that all current chevrolet performance BBC engines are based on. The only issue you would have is that because it is a fuel injected engine stock, you would not have the exhaust crossover in the heads for the carburetor intake manifold which would make it less happy during cold weather driving, and you also would not have a mechanical fuel pump boss. That means you would need to run an external electric fuel pump, which has been an issue for several members here.

 

[Mark Jones]

Are you Vortec Pro from Team Chevelle? If so you guys all need to listen to this man!

Yes

 

[BigDaddy72]

I’ve had 496’s I’ve built in 2 square body’s and one 94 k3500 they all work great for pulling. As far as gas engines go.

I’m sure Cummins guys will jump all over that and that’s ok.

You have gotten a bunch of great ideas here. Now you just have to decide what fits your budget needs and preferences.

Best wishes to ya on yer project!!

 

[Grit dog]

Ya, I was going to say 12valve ftw.
it wins the “less wires” to hook up and The most Easy power For towing and pro use all in one.
1 wire and 700-800 ft-lbs without even taking the valve cover off!

For gas towing and pto gotta keep the 4 speed, but a 70s RV with a 454 and turbo 475 trans is hard to beat for simple tough setup.