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The desire to go faster...

mountainexplorer

mountainexplorer

1/2 ton status
Joined
Nov 14, 2001
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Location
Spokane, Wa./Ione, Wa
It's making me scheme up some ideas for a mud race rig.

For one, I'll never have the big bucks to sink into a mega-horsepower motor built by a professional. I also currently lack the tools to be able to build a tube framed rail.

But I do have the parts to throw together the following:

(Assuming "Street and Trail" Class for mud racing- Under 36" tall tire, street legal, registered, no nitrous or alcohol).

'79 Chevy shortbed. Shaved 14 bolt FF rear, welded spiders, Pre-'76 Dana 44 front, open, 4.10 gears, TH350 tranny w/stall converter and NP205, 8" springs, 36" Goodyear M/T tires, small journal 327 with 11.5:1 domed pistons, 64cc Camel hump heads (1970 year w/accessory holes), gear drive, 1.6 intake/1.5 exhaust roller rockers, Edelbrock Performer RPM intake, Edelbrock 625cfm carb, Headers, 3" exhaust w/40 series Flowmasters w/dumps right behind the mufflers. Cam possibilities: (yes, I want "big")
Solid: Duration-285, lift-.532/.555 or
Duration-300, lift-.562/.557

And, unlike everything else I have, NO heavy winch bumper or winch, no excess of accessories, and I may even try to gut out/strip out/or cut out any un-necessary weight like the floor of the bed, interior trim, etc...

It's no rail, but it's not for X-class either. I want to be able to drive it to the races and enter it. I'm getting tired of this slow motion crap with the rigs I have now. I'm out to put on a show, or maybe even get a trophy. /forums/images/graemlins/thinking.gif
 
I wouldnt use the Goodyears, maybe some type of swamper (BOGGER) /forums/images/graemlins/thumb.gif
 
Weld the front.

Run TSLs in the front/Boggers in the rear.

Consider a 10 bolt or 12 bolt for the rear.
 
Yeah, my specs arent fully perfect, but a majority of what I listed is just stuff I have right now. Last Saturday, the guy who got 1st place in Street and Trail class was running the Goodyear 36's.

I'd go for Boggers as long as my 327 could spin them like nothing. My other possibility is a 350, but I already have a 327 together as a shortblock. (trying to stay smallblock for the thrift of parts and less weight.)
 
Is this for a bog or a drag?

I agree with swampers, run skinny swampers up front and boggers in the rear. Also weld the front diff as well as the rear.

If you really want to get into it, I would run less lift, and remove some rear springs, kind of makes it unfriendly for the road, but it will launch much faster off the line.
 
The motor sounds like it should be able to hold the RPMS well, If this is a fairly shallow drag, I would suggest going with 34" swamper fronts and 33" boggers in the rear and running something like a 3.73 gear.
 
When you put that motor together you better do a lot of clearance checking. If that dome is as large as I think with 64 cc heads yeah well valves don't make a pretty sound bouncing off pistons. Port those heads. Sure they flow decent but every bit of flow helps, especially when you spin RPMs as a 327 should.
 
I'd probably put 4.88s in it and run an air shifter. Get it going and once you hit 2nd you'll be moving.

I'd also suggest you put a 350 crank in it. No stock head really flows enough to take advantage of the powerband that a 327 will make. The 350 crank will make a, "Factory stroker" out of your 327. /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
 
[ QUOTE ]
I'd also suggest you put a 350 crank in it. No stock head really flows enough to take advantage of the powerband that a 327 will make. The 350 crank will make a, "Factory stroker" out of your 327. /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif

[/ QUOTE ]

You can't stuff a large journal 350 crank into a small journal 327 block (as he said he had). At least not without major machine shop work. $$$$$$$ 327's rev like crazy anyway, more so than a 350. There was never a small journal 350 made, but there was a Large journal 327 made in 68/69 Very hard to find though.

With the right cam and gear choice he should be able to keep some bogger's spinning. I would invest into a high quality valvetrain. Roller rockers, screw in rocker studs w/ guide plates, high quality valve springs and maybe even a stud girdle. If you build it with a solid cam, you will be able to rev up past 5,500 to 6,000 and up. You will be getting most of your power at 3,500/4,000 and up from there. For that matter I'd stay away from a dual plane intake and move to a single plane (Victor Jr or similar) so that you can support the airflow at the higher RPM's.

By running a 327 you will be giving up displacement, but you can make power by being able to rev higher than most big blocks and even 350's and still be making power. High RPM's from the engine will give lots of wheelspeed if you gear it right for the tire.
 
I would go with about 4" of lift, 12B or 14BSF in the rear 33" boggers all the way around, I would use that 400 you have instead of a 327, and totally gut it for the least amount of weight.
 
I'd invest in a Detroit in the rear. As long as your foot's in it, it'll be locked up. No need to abuse the rear axleshafts & tires while driving to & from the comp., especially if you go lightweight with a built 10B or 12B.
Welding the front is probably OK, just unlock the hubs before steering when out of the mud.
 
My SB400 is in my '84 K5. It runs strong, but it's kind of a mild motor for what I want this truck to do.

I was going to put the 327 in my '68 3/4 ton 2wd, but then I'd start hot rodding it, and I don't want to abuse that truck trying to race people on the street.

There's this other rig with a Model A body on a K5 frame with a 327 in it. That motor screams. When I first heard it, I thought for sure it was a big block.
miller1.jpg


They run a 12 bolt rear, which I know has a ground clearance advantage, but they go through gears and parts alot. Also, 33's are a bit small for some of the mud. Last weekend, in the Blue Blazer with 35's, just lining up I could feel the mud dragging under the axles. The Yellow Miller rig runs 39.5" Boggers in the rear and 38.5"s up front now.

I'm planning on gutting out any extra weight I can. Anyone know if a stepside or a fleetside box weighs more?
 
Another Detroit isn't in the budget. This thing wouldn't really be driven on the street all that much anyway. I don't know if I'd weld the front up. I don't want to be constantly breaking shafts and u-joints. Ive heard also that a locked front makes steering "interesting" trying to go straight through a pit.
 
Trailering is better, cause you don't wear it out and if you break, you're safe.

But my whole idea is being able to drive it there under its own power. Last Saturday, I entered my Blue Blazer (daily driver) in the "Street and Trail" class. These vehicles are supposed to be street legal. I noticed, a majority of them were trailered in (mainly the fastest ones).

Now, of course I'd trailer in a "Modified" class rig, if I built it for that class, but if you saw the competition, you'd understand why I want to stay in "Street and Trail". I entered the Truck Blazer as well last Saturday, and probably got one of the slowest times for Modified (but my poor motor is dying a painful smokey death). But if I capped off the header dumps, it could have driven on the street.

A vehicle impresses me more if it can perform well in the pit as well as drive on the road. Like the Big Crew Cab...
38" tires, 9" lift, built 396 BB... it used to get driven to the races TOWING another rig, then would get entered itself, even run with nitrous a few times. And at the end of the day, got hooked back up to the trailer, and towed another truck home.
 
I know you said not high HP big $$ motor, but these are the 2 guys that dominate the comps where I live.

Not sure on the year53-55, but 383 TH400 205 14BSF and a 60 with 37" Boggers now used to be a 44 with all the same gear but in a 73 K5 and he is fast he ran a 3.21 (100ft) at out last mud drags /forums/images/graemlins/eek.gif
110_1094.JPG


and this guy. Not sure on powertrain. I know he has a 502 Ramjet, but 14BSF and D44 with 39.5" boggers.
110_1099.JPG


I got third behind these guys /forums/images/graemlins/thumb.gif, one of them always wins
 
Cool rigs /forums/images/graemlins/thumb.gif

Competition is pretty stiff here. This here is one of the rails. The new bigger motor spun a bearing, so they threw the old motor back in, and still took 1st place in X-class and also fastest time of the day last Saturday. Heres the last minute rush to get spark to it, using the distributor out of my Crew cab.
3728010.jpg

randy1.jpg

Both he and his wife run it, and she beat him and got 1st, and he got 2nd in X class. This was a 150ft pit and they were in the mid/low 3 second range. Probably the fastest my distributor has ever spun. /forums/images/graemlins/blush.gif
 
[ QUOTE ]
Another Detroit isn't in the budget. This thing wouldn't really be driven on the street all that much anyway. I don't know if I'd weld the front up. I don't want to be constantly breaking shafts and u-joints. Ive heard also that a locked front makes steering "interesting" trying to go straight through a pit.

[/ QUOTE ]

I mud raced for about 8 years, quit in 2001 because the rules were getting stupid. I ran altered stock class, one class up from pure stock. Trailered my truck to all the events. A welded rear and front makes a world of difference. It actually helped the truck go straight in the pit. Also running tires slightly larger in the front helps keep the truck nice and straight. Running soft springs in the rear, or removing leaves from the pack helps alot. You want the truck to move right off the line, not spin the tires before moving. For a couple of races I lost at least a half second spinning on the line before the truck started to move. After welding the front and rear, putting boggers on the rear, and removing half the rear spring packs (stock springs with a four inch block), it hooked up and launched hard off the line.

For comparison, I used to run down in the low 4 second area through a 200' pit. The mud was usually about only 8" deep.
 
I've heard that being locked in the front makes steering control harder.

And also, doesn't a higher gear ratio up front aid in steering control?, cause the fronts spin faster and help "pull" through.

I have a pair of nearly new 39.5" Boggers I'm saving for the rear of another rig. I think those will go on the rail when we build one, whenever that will be. I'll worry about X-class after first dominating Street and Trail. /forums/images/graemlins/tongue.gif Just kidding. Nothing I own will ever be fast. /forums/images/graemlins/doah.gif
 
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