# Stump Puller



## crw432 (Dec 24, 2000)

I need to rebuild my 454 in my 1 ton 3+3 and would like it to have more low end pulling power. I went the other direction in the last rebuild. I am an old hot rodder at heart and built a 450+ hp monster that ran great over 3500 rpms, but would not pull worth a s---. Need a little help on building a mild mannered stump puller.


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## Jeff's Classics (Nov 15, 2000)

I have been considering the same for my '76 Suburban 454. The key is to look at low RPM operation. Start with a mild compression (maybe 8.5:1 or 9:1) rebuild, keep the valves in the heads stock, but you may want to have a mild pocket porting job to clean up the combustion chambers and make them more efficient. Use an Edelbrock Performer intake and the smallest tube size equal-length headers you can find. I am planning to use DynoMax CeramCoat, which are ceramic coated and run a little over $200 for the set. Use a cross-over pipe in the exhaust system as close to the engine as you can fit it. Keep the QJet, but have a high-quality rebuild done on it, including new throttle shaft bushings. The trick is the cam...I haven't picked on yet myself. Called Comp Cams, they recommend a Comp 256H, which is pretty mild but is supposed to be good for towing.
What transmission and rear end gears are in your truck?
Jeff
http://www.jeffsclassics.com


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## 84'GMC4x4 (Oct 6, 2000)

Jeff, just curious, what does the exhaust crossover do for you? i would presume that whatever benefit it carries would carry over to a 350 w/dual exhaust also, no?

Greg


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## TLS (Jan 31, 2000)

'84,

An exhaust crossover helps low RPM power and also alleviates the droning of the exhaust at idle, however, at WOT the exhaust just whizzes past the crossover and out. Yes, any V-8 engine with dual exhaust will benifit from this addition. There are a few experts on cams over at the forum on http://www.454ss.com It is a real sience with cams, but all the work has been done these days. Just stay small. A big block can "eat" more cam duration and still be mild than what a smallblock can have.


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## crw432 (Dec 24, 2000)

I have a Turbo 400 with 4.10 gears....been trying to find someone who has put an Allison at545 in a Chevy truck, but no replies, I pull alot of weight, around 18k total. I eat a trans once a year.


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## TLS (Jan 31, 2000)

crw432,

18K GCWR is a lot of weight, however, something is wrong with your cooling system for you to be smoking tranny's every year. Are you running in the mountains? You have the Texas heat to worry about, however, you have plenty of room for more tranny coolers. Try a remote located cooler with its own elec. fan. Keep the tranny fluid out of the regular radiator alltogether and run two aux coolers out front of the radiator and run the fan mounted one under your passenger seat (outside of course) right before the return line enters the tranny. Run a 180 deg stat. and a good radiator with an external engine oil cooler and a stewart high flow water pump. Good clutch style fan and shroud. You may want to think about a 4L80 swap to give you an overdrive and (very important for heat) a lock-up converter. They have kits for non computer applications (Jet). As long as you dont mash the go pedal with that 12,000 lbs in tow, the tranny should survive more than a year anyway.

Happy Towing


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## John DiMartino (Jan 22, 2000)

For low end power,stick with the round port heads,recantgular port heads are for hi RPM's,not good in a truck engine.If your going to swap in an Allison 545,and totally rebuild the motor-might I suugest you swap in the B5.9 Cummins turbo diesel,the 73-87 style Gm's accept that engine nicely,and a mild version will give 300-350 hp,and 700-900 ft lbs at the wheels.I bet you can find a used motor for 3-4K,now that will pull 18K like its nothing,and low end will never be a problem.If you pull; much the saving s on fuel will pay for the swap,you''ll likely get double-to triple the mileage pulling that you are now,and double empty.Just a thought,since I love the 73-87 style GM's,if i find a clean one,that's the engine thats going in,Ill even buy one with 150K on it,since its got at least that much left in it,maybe 3-400K more.There is a guy on the TDR that has an allison 545 behind his Cummins,he regularly tows over 20K with no problems.


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## crw432 (Dec 24, 2000)

Ok....maybe I should be more specific...I have had trans problems, but not the same thing over and over. The first time it just went gone,bye-bye.....the second was a converter gone at around 60k since the rebuild. I know that I am hard on the trans and it does seem to be the "weak link" in my rig. I have an external cooler with an aux fan for the trans, plus another aux fan with the a/c, I run a all aluminum radiator (aka racecar) with high output pump..........never had an overheating problem, just hard to heat in the winter. Just want to do something special I guess.

Craig
1983 C30 3+3 454 450+ HP (HERE is the power...stroke it!!!!)
1997 Dodge 3/4T 4x4 V-10
1978 Blazer 502 Cu In....Monster


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