We are going to have our first truck pull locally. I have never pulled before but I just read the pull thread that is posted. That is very good but i am not going to pull with my duramax even though I know it will out pull my 1984 chevy. Someone told me that there is a key speed that you want to stay around when pulling. They told me figure up whatever you can to get your speed to 25MPH. Is that true? Like i said these are all guys pulling with 80's model chevy's with small block and big block gassers. The following are the specs of my truck to see if anyone can give me their input...

1984 chevrolet
Dana 60 front end open w/ 456 gears and 14 bolt rear w/ 456's and a detroit locker
small block 350 with about 400 HP RPM power range 3200-5000
Tranny is a built TH350 (3 speed automatic)
NP208 t-case (2.61 :1 Ration in low lock)
Tires: I will have to run smaller tires because they donot allow anything over 35's. So I will be running 305 70 16 toyo open country mt's ( the stadium will be packed dirt )

My theory: Run in 4 wheel drive lo lock the transfer case and pull in 2nd gear. After doing the calculator I will be pulling the sled about 27MPH.

Please give me your opinion and / or advice!

With that motor/tranny/transfer you will put it in low range and 1st gear, don't even think about running second gear.

(gear*t-case reduction*ring and pinion).

Your combo in first comes out to 36.57:1 which is low (high numerically) and your combo in second comes out to 18.09:1 which is high (low numerically). Most shoot for high 20's.

If you had a monster motor you will most likely rev to the moon in first gear but still not have quite enough for second.

Hopefully your motor is low on HP and it should put you into a good HP/gearing range. It would be nicer if you front end were locked as it would bring down RPM's some. Definitely run your hitch at the max height and freight up to the maximum weight. My only concern would be over-reving your motor if traction is limited. Do you have a rev limiter?

Give it hell and let us know how you did.

Small block like RPM. My old 400 didn't run good till you hit about 6000 then it took off. Try to get a little taller tire to bring your speed back up, like a 35 and you should be good.

Thanks guys, the pull is actually in July and I still need to get all of the rules but y'all gave me the info that I need. I don't really know what my truck will do on 33 or 35's because it has only been on 38.5 boggers. The first pull is going to be interesting. Hopefully i will get to pull twice so I can try 1st gear on 1 run and 2nd on the other. I'm sure y'all are right on staying in first but I guess i'll have to see what it'll do. O and about the rev limiter... My rev limiter has always been 38.5 x 15 Boggers... lol They will not let it over rev, it usually sits about 5200-5500.

Any idea on cam and valve springs and how old?

The valves springs and more importantly valve float is going to be what I would fear most on a street engine that starts reving north of 6500. Although you can always use the polish rev limiter (i.e. your right foot).

It will be interesting to see how you do. If your tires get a good bite, I would say you should do well depending on your competiton.


Thanks guys, the pull is actually in July and I still need to get all of the rules but y'all gave me the info that I need. I don't really know what my truck will do on 33 or 35's because it has only been on 38.5 boggers. The first pull is going to be interesting. Hopefully i will get to pull twice so I can try 1st gear on 1 run and 2nd on the other. I'm sure y'all are right on staying in first but I guess i'll have to see what it'll do. O and about the rev limiter... My rev limiter has always been 38.5 x 15 Boggers... lol They will not let it over rev, it usually sits about 5200-5500.

I wouldnt even think about pulling in second gear. Put it in 1st and let her eat.You will need all 5000 of them rpms and when it shifts to 2nd it will pull the motor down losing rpms, which will cause you to lose ground speed and momentum (sp). As the rpms fall it will shift back to 1st gear and as the rpms come back up it will shift into second again pulling the rpms down again if you leave it in 2nd it will do that the whole time and it will not pull as far as if you put it in 1st.

i would definitely try and find some 35 mt tires that are about 1/2 worn and stick with first. yeah you're gonna rev but at the end atleast you'll have some tq. left to give it that extra yank you'll need. who knows if you draw a late number watch the other trucks and steal their notes. if the sled lets guys get out quick with speed then i might think about tagging 2nd but that'd be the only way.

I will tell you my combination in my '77 K-30:

I have a granny-low 4 sp, NP205, 4.10 gears, and run 33" BFG A/Ts.

At 7,000rpm in my 454, low range in the case, and 1st gear on the stick, (not granny) I usually move the sled at 19mph according to the sled operator's speedo. This makes a final gear ratio in the high 20s. 3.58x1.96x4.1=28.76888

My 454 makes an estimated 500HP/500TQ +or-. I have found this combination to be about the best all around gearing for the HP that I am making. On soft tracks I am a little too powerful, and on tight tracks I can be slightly underpowered. IMHO, that puts me right in the middle so that I can compete in most places, and not have to change things between pulls. (read: $$$$)

EDIT:

Chevybogger, I just looked in your garage, and that is one SWEET looking rig you have there. I hope to make my '77 look that good soon. I have a grille/rad support out of a '91 Sub like yours that I will put on the old iron.

However, I don't mean to rain on your parade, but it is my experience that the lifted trucks don't pull so well, especially with a 12" lift. As soon as you get some serious power the u-joints wont last long, and breaking will not win you any pulls.

This is just my opinion, so don't be offended by it, but your truck is way too nice to be stomping around in the mud anymore. Take out the lift, and buy an old late 70s $1,500.00 rust bucket clunker to put the lift on and let that be your mud truck. After 15 years of truck pulling, I have seen some beautifully restored trucks. Pulling is a great place to enjoy your truck, and know that you wont, most likely scratch it anymore. Can't say that about mudding.

Also, I suggest finding a set of brackets for the front quad shock option that was offered on the 1981+ 1/2 ton, 3/4 ton trucks, Blazers, and Suburbans. I got my quad shock brackets, and hardware from my Chevy dealer's parts department. I don't know if you can still get them or what their part# is, but having them helps keep the front end settled.

A buddy of mine had a nasty hop in his '84 sled puller, and the only thing that got it to stop hopping was removing the 4" lift, and putting the quad shocks on the front.

I just looked at your garage, nice looking rig!

Engineer, thanks for the specs on yours. That really helps me. Thanks for the good and bad comments, I agree with most. I agree with you on not wanting to put it in the mud again and getting another old beater. I do like the sound of not scratching it again. About the lift and u joints... I agree that it is most likely too tall and the weak link is my front driveshaft u joint attached to the D60. I am not sure if I will have a bad hop or not because it never hops when I am pulling people out of the mud or when I played tug o war with my buddy ( he had about 8" blocks in the rear of his and he can't say the same... his took off bouncing and he snapped the shaft from his SM465 to his NP205. ) So I will at least see what it does this first time. If it starts hopping then it will probably only get 1 pull but if not I hope that I can make a decent pull.

Leadfoot, thanks for the comment!

Cb-

You may not have the hop issues with your lift. Typically a large lift will require the springs to have a high spring rate, and thus they will resist axle wrap. If you are still running the factory u-joint on the DANA 60 it will be a really wimpy 1310 series (Spicer 5-153x). I am running the factory 1310 u-joint, and haven't had any issues even after 15+ years of pulling. However I am not running any lift either. If I ever build any more power, I may see about upgrading to a 1350 series in the front shaft. My front CV joint is the Saginaw (4-bolt flange) style, and it uses the 1330 series u-joints. The Spicer CV joints that are found in the 70s Chevys, (the one that has the bolts that thread in from the T-case side) also uses the lighter 1310 series joints, so keep this in mind if you are swapping around drivetrain parts.

You did the correct thing if you do deceide to make your truck a full time puller by putting the one ton axles under a 3/4 ton frame. The 3/4ton frame makes for a lighter truck than does the 1-ton's. A lighter truck will allow you more flexibility in placing weight on the front of your truck. If they will allow it, you want as much weight out front as possible. All of the places that I pull at allow you to run front weight brackets, but limit you to a 60" measurement to the front of the weights from the C/L of the front axle.

A couple other quick points....You will want to block the rear axle as solidly as possible. I recommend "axle stools" that block the rear axle solid like a bump stop. Make sure that you "set up" your rear axle blocks after any weight is put on the front of the truck. Doing so in reverse will lift the rear of the truck off the stools after the front weights are applied so that it will have some squat when the sled applies it's weight. Avoid this if at all possible. My point is that you want the rear of your truck as soild as possible when they hook the chain to you.

One more important thing. Traction bars.....You will want bars that connect from the rear axle to the frame. The brackets for the rear axle should be welded under the axle housing, and the traction bars should extend to a point on the frame at least 1'~2' ahead of the point where the cab, and bed meet. Without these bars, your frame will arch, or flex, and will allow your hitch to drop when the sled applies it's weight. Eventually, without the bars, your frame will have a permanent arch and the gap between the cab, and bed will get larger, and larger.

IMHO, the axle stools, and traction bars will do more to make your truck competitive than possibly any other modification that you could do.

Also, get your hitch as high as possible. 26" is what we are limited to where I pull.

Good luck!

I hope that Chevy kicks some butts. :gr_grin:

I forgot to add...

Air up your tires in the rear as tight as possible. My BFG A/Ts call for a max of 50psi, but I throw 60psi in them because I usually trailer my rig to the pulls. I usually run 50 psi in my RF, and 30 psi in the LF. The torque of the engine will load the RF tire, so putting more air in that tire kind of keeps the front balanced.

Putting more ballast weight on the LF helps as well.