Lmackattack

I would suspect you could go behind the door panel? It would be a custom install for sure might look into that for my r model.

I can't locate my performance chart but I recal the 250L and 275L made peak torque around 1050rpm. That's about 300rpm lower than a 2100 rpm pump. What I was trying to get at was if he wants more power for the hills. He shouldhave his pump re calibrated , set to 2100 rpm with 350 hp specs.... His turbo and injectors should be the same, cam may be different but that's all pretty easy stuff to check. If its that simple he can go from a 275L to a 350HP 2100 rpm pump. Then with the 350 spec have the shop bump up flow + 10% to 15%. Not only will he have lots more power, more road speed and more rpm to work with . All for around $400. Not a bad price for all that gain... I drove 2 diffrent 89 R models both with 350 and a 9 speed. Remember one trip to long island and back and the truck was getting 6.2 mpg with a van trailer. Pulled the hills great with a load of mail I was hauling. Went thru upstate ny and never dropped below 40mph on any of the long hills. That was a fun trip.

Give it another week. If no reply...Keep the cash find a new title. Plenty of scrapped trailers out there or other options. Just be smart about who you ask and who you tell...

Not sure about the cam... Would have to ask a Mack mechanic to be sure. I have a friend that converted a 300L to a standard 300 has a 5 speed with overdrive in 5th. Think it had 4.42 or 502 gears? Truck had more go with the 2100rpm pump. and would do about 70 mph after RPM and fuel was turned up. She did drink fuel tho 5mpg maybe 5.2mpg....but it only had 5 gears so hi way speed was 1900rpm all day.

Also just noticed that's it's a 275L.....yuck! Under powered and low rpm... That is fleet spec for LTL in my opinion. Check with a dealer on your options but im almost certain you can Have your pump converted to a 350 / 2100 rpm and reset timing and it will be a different truck. 350 and a 9 speed will pull much better and still gets good mpg with your overdrive. It will be about an 82mph truck, still have power and low end grunt. Drove one with that set up and loved it...

Difference will be in the pump and timing. 300 was a maxidyne and used less gears than a 350. At least that's how it was with the r models. gearing it slower will improve pulling power and it will be most noticed out of the hole. However I don't think you will see a huge gain in speed on the hills. The small displacement Mack just won't pull like a big cat. I have driven 400hp Mack's that pull good on hills but still will not keep up on the hill following a 400 cat. Being that it's a dump truck the smaller tire is a better choice.. That's my .02

That sounds about right. But am Surprised how light your alum step deck weighs. My RS700 and 22' steel frameless end dump weighs in at about 28,500 and it's half the length!

was going to say look at that Vin number close when you go to buy it! Nice truck tho and great specs...

Hmmmmm I don't remember this guy.........

That guy is good! Look how smooth he was. Lol

Please do... I love seeing all the old Chicago Mack's... ,

Yes a double over will give you faster road speed. To be certain you need to check your rear end ratio and do the math with the 18 speed ratios.

That's god to know. Had suspectd thats why mine fluttered...I will have to plumb mine into the cross over pipe on my 285....thanks!

the celli b model I took home I used everything but sheet metal,engine,trans,fuel tanks. I Sold most of those parts to mike. I later bought a rust free cab out in long island and used that cab. I sandblasted frame and axels on the celli truck and put in a non turbo 711 from a reliable wrecking b model I had bought a year before. Basicly I bought 2 b models in rough shape and put the best of both trucks into one. The reliable wrecking truck I should have never bought. I was 20 years old and had the I can fix anything attitude. That truck had rust inside of rust ! Double frame, no floors ,cab was shot! Had a 711,quad 5.73 on camelback The celli truck was n pretty good shape. has a single frame, budd axels and a 673 turbo with a quad with 5.73 on walking beam. I never tried to start it as my 711 was a good runner.

My boost gauge flutters as well and have not figured out why. It's a auto meter gauge and when I first installed it it was pretty steady. Now it flutters +/- 5 psi. I was thinking it might be because of where it's tapped into? It's tapped into the far end of the manafold and possible that when the intake valve on that cyl opens the pressure drops and then builds when it closes again...repete ....and you get the point. Not sure and haven't looked into it much...to post a vid get a u tube account,upload it and then link ( copy&past the url) the video here

Looks great! did he just get painted? thought I saw it at the yard a few weeks back and it was red. Looks like some new tank straps and new marker lights. Good to see he takes care of the old truck

you will need a machine to pick it up a R model cab. I would figure somewhere around 800lbs with seats and HVAC installed

Here are a few pics of the rescued celli b models. They were. Frozen in. The ground, trees growing up between the Rails.

Well that's good news. Pull a load with it and see what psi it's making. Bob tail it's hard to put a good load on it. It should make the most boost around 1800-1900 on a 2100 rpm engine.

Down on the south side is where I see all the old r models . Chicago suburban express had a old r model but haven't seen it Ina while. I still see some RD's pulling vans locally. But Most of the r models i see are dump trucks both 6 wheelers and tractors. What I miss seeing is a busy intersection with 3-4 r models waiting for the green light. when they all took off it was a good smoke show out the straight stacks while watching them all shift gears at about the same interval. They all were 285 or 300/6 speeds,pure music. My first time driving a mack i timed my shifts by remembering how they sounded when I was a kid. Ahhh the good old days..

Is that like a long hood model? Looks like it was done up nicely.

To be honest I saw more Mack's around NYC than Chicago. We still have lots of new Mack's but NYC had more older and heavy Mack's.

285hp / 2 stick 6spd / 4.17 rears...

vinnyDon't see a lot of u models around here. However lots of dm roll off and still a few dm cement trucks. I cant recall the last u model tractor I have seen on the streets..

Looking good brad I think pj bought the same grill to make his RD a contractors special.......how bout some pics of your old mans R model. Always loved that truck.