Big Block Chevy mods for towing

P

PDoane

New member
I pulled the Chevy 454 TBI motor out of my 23' Class A Winnie due to various engine (burned piston and warped exh mani) and tranny (so far just a leaky seal) issues.

With so many different mods for big block Chevy motors out there, does anyone have any recomendations for mods suited for towing (24' enclosed/7000lbs)?

I have been contemplating the Banks Intake/Exhaust system, but don't think much of the price ($1200) and don't need anything but headers/manifold. Have also been toying with the idea of a Gear Vendor under/overdrive gear splitter unit, but also think $2500 is a lot. Even found an Eddlebrock TBI to MPFI conversion manifold for $1200.

In the lower buck category, there are Crane and Comp cams for for TBI 454s. Hedder has headers listed for Class A RVs too.

I assume I need mods for low end torque not high end HP.

Comments/corrections/suggestions would be appreciated.

Thanks

Peter
 
Not sure what year you have, but sounds a lot like the one that GM makes a direct swap in 502 crate motor for. They do it for Suburbans and pickups, even did emissions. Not sure of any details, but it's something I'd be looking at for sure.

As for Banks, $1200 would be very cheap, if your talking about a whole system. I see folks spending $3000 or more all the time, and being happy. Of course, good flowing headers can be had a lot cheaper, it pays to shop around.


Edit: quick google search yielded GM Performance Parts part number #88890533, intended for 91-93 trucks. 515 foot pounds of torque!
 
Put the Banks system on a TBI 454 motorhome, it was the best $ value for performance you could do. Fuel mileage increased by 30-35%. power by at least as much.
 
Have a friend that ran the gearvendors overdrive on the 454...he was estatic at dorpping the rpm so much and got several miles per gallon better. He thought the investment was very worthwhile.....makes the 454 happier at 80mph, too :D Chuck
 
The thing that kills the 454 is heat. On most motorhome the exhaust is not large enough and is so long it causes a lot of heat build up in the engine. A lot of motorhomes only have a single 2 to 2 1/2 inch exhaust pipe which is not enough for a 454.

The Comp Cams towing cams are really good for the 454. Also install stainless steel valves in the motors. I like the stainless steel valves because the 454 can burn up the exhaust valves and the stainless steel valves are almost the same price as stock valves for the 454s. Give Jegs or Summit Racing a call and tell them what you are doing.

Headers will help the flow but can rust and have leaking problems and may be a hard fit on a Class A.

The last 454 I did, we used the Comp Cams, stainless steel valves, new valve springs, stamp steel roller tip rockers, cleaned up the ports, headers and a good dual exhaust system. It was in a 1988 1 ton, 4 wheel drive, crew cab, dually (The Beast). In 4Hi it would spin all 6 tires. Burn out marks from a dually look a little funny when you see them. :)

If we stayed out of the 4 barrel we would get 11 mpg cruising right at 65 - 70 mph towing a 24 enclosed tag. It had a 4 speed with 4.11 rearend.

If you are on a budget, I would first look at the exhaust system. Make sure you have a good cooling system. Since you most likely have an auto trans I would make sure you have a good trans cooler with a fan. The auto trans can put a lot of heat into the motor.
 
Thanks for the input guys.

I have ruled out any kind of crate motor for now because the block was "saved" (no cracks according to magnaflux and honing only to clean up the cylinder). Other than maintenance items (rings, new bearings, timing chain/gears, oil pump, etc), the one piston is all that I have replaced. I like the idea of an emmisions type 502, just don't have the $/can't justify the expense right now.

I did order a Crane Cam (# 134112) for it, along with stiffer springs and associated spring hardware. For now I am not upgrading the valves, just recutting the existing valves/seats.

Since I was changin out the water pump as a preventative maintenance item, I went with the higher flow one for $20 more.

The exhaust on this Winnie is already 3", so unless the OEM cat is blocked, I won't be going with the Banks Int/Exh kit. A replacement OEM exh manifold (with separate flanges to prevent warping) was about $300 so I'm trying a Heddman header (#69120) for $130. You do get what you pay for though because this thing looks cheap/flimsy/subject to fast rusting. I haven't fit it (or the custom tubing to tie it in with the rest of the exhaust), but it was listed for Class A motorhome. I may fit some brake ducting from the front to the rear exhaust areas as several people have told me to be wary of exhaust overtemp.

Still no update on the tranny, but others have told me/read on truck forums that the Gear Vendor splitter has trouble towing large loads and pointed out that servicing with it installed becomes a much bigger hassle. I will say that there was an OEM tranny cooler built into the radiator and I added another separate one in series with it when I first bought the RV, so I hope tranny temp isn't an issue. I also change the fluid/filter regularly.
 
Remember to get a new oil pump. Did not get a high pressure but get one with a high volume is OK.

Also check the push rods to make sure they are straight and the oil passage in them is clean.

A new timing chain set is a good buy also.
 
You must log in or register to reply here.
Back
Top