LDS427 with no power and low boost issue

[Brian Kemm]

Ok so here goes. I bought a 1971 M35A2 that had the LDT465 removed and an LDS427 installed in it. The swap was done very well with the exception of the guy not welding a bung in the downpipe for the thermocouple so the pyrometer is inop. I will fix that this weekend. It has been shortened and bobbed and the work was done very well with everything exactly where it belongs. The truck is on the tall singles and is totally gutless. I have not checked my supply pump pressure yet but with a boost gage hooked up I might see 1.5psi at 2000 rpm. #1 should I be running this thing up above this rpm range towards the end governed engine speed of 2800 rpm to really see any power or will it actually lug? I have to do a rediculous amount of shifting between 3rd and 4th for normal driving to really go anywhere. Im not new to trucks or diesels as I am a master driveling tech with class 8 heavy trucks and have been wrenching on big rigs for 23 years, however this is not a 15 liter Cat with an 18 speed this is a displacement challenged engine with a tiny little 5 speed and it needs help. I will be going to my yard this weekend to tinker with it so any suggestions are welcome. Yes it has fresh filters, a new fuel tank and lines, the engine has 15 hours on it since TEAD rebuild and crating in 1984, I have the old LDS465 in the 427 shipping cask. The pump appears to be a late G code pump. It did turn the fuel stop two flats only to get the same result. The smoke plate is marked 7 degrees in the governor housing. #1 I know I have to get the thermocouple welded in ASAP before I put any more fuel to it so I can witness any temperature changes in egt. Am I on the right track? A few years ago I experienced a cat 3306 that was out of framed and only run once then the truck sat for 3 years and the governor flyweights stuck resulting in alto of black smoke and really crummy performance. .... Im wondering if im experiencing the same possible problem due to the engine being in a cask for 31 years.

 

[NDT]

Welcome. Tall singles means 47s or 53s? The 427 should fly especially bobbed. Are you getting lots of exhaust smoke, I mean Prius Repellant grade? Should be. TEAD would not have been rebuilding 427's in the 80's, all the 427s were junked long before that.

 

[gringeltaube]

.....TEAD would not have been rebuilding 427's in the 80's, all the 427s were junked long before that.

Not all... I bought 4 of these LDS427-2, TEAD-rebuilt engines and all rebuild tags indicating '89.
Supposedly they all where ran-in and dyno-tested, to put out 150 Hp @ 2600 rpm. But I can tell that not all of them had the same power. The first one I put in one of my M35 was about as gutless as the OP describes. It also never ever smoked under load. Then, some timing adjustment and turning up the fuel cured most of the problem.
Just don't expect this to be a "powerhouse"...


G.

 

[Brian Kemm]

The truck is on 47's. And yes it smokes almost as much as my 1970 Mack r600 St. The TEAD rebuild tag is from Tooele army depot marked 1984. Guess ill double check the pump timing and get the thermocouple welded in and then go over it some more.