GM/Chevy 250 Conversion in 90/110/130

O2batsea

Well-known member
Just that putting in a big engine doesn't necessarily mean that the horsepower potential it offers will be available/attainable in real-world driving
 

rocky

Well-known member
I only know of one 250 conversion that was completed but reusing the old diesel tank clogged the fuel filter. So a new tank is on the way. Its an incredibly smooth performer. To the extent that its all too easy to think its stalled out.
 
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RDavisinVA

Technical Excellence Contributor
We swap the fuel tanks in vehicles all the time.
There is one here that was perfectly fine without leaks, that had a lot of sludge inside.
Was thinking of having the tank steam cleaned or pressure washed to get the inside free of diesel sludge, but with new tanks so cheap, why bother.
 

RDavisinVA

Technical Excellence Contributor
This should contain enough info to get started: https://en.wikipedia.org/wiki/Horsepower

I think what was being implied was that if a Corvette engine is transplanted in a Defender, that it probably won't reach the optimal RPM ranges that the engine was designed to operate in.
It will have a power band defining it's performance that may not be suited to the host vehicle.
Since HP is a basic function of torque at a given RPM, an engine with 150 HP sounds low, but when you examine the power band that has 250 ftlbs of torque at say 1,600 RPM, then that would provide excellent performance and would get-up and go both on and off road.
Compare that to a power plant that has 3 times that performance and most of it goes unused because you'll either break something or loose control.

I sometimes enjoy seeing a "tricked out" Bronco or Blazer at an off road event with high output engines and ultra loud exhausts.
They rev it up and twist a driveshaft or explode a diff and there we are riding past them going slow very quietly, presumably without drawing a lot of attention to ourselves.
 

O2batsea

Well-known member
IDK if this was touched upon in this thread but the harmonics of an inline 6 are such that they are about the smoothest running engine, which is why they run so quiet. Also, the stroke over bore length makes them ideal torque producers which is what you want for an off road vehicle. I think Land Rover was on the right track when they put the 6 into the NADA 109 but the engine was such a mind boggling piece of shit that the experiment failed. If they had put in a ford or chevy six those trucks might have become famous instead of being tossed aside as too much trouble.
My Willys Hurricane 6 was a great engine even for a flathead. It just went, no matter what.
 

Robert

Well-known member
The Power I know is measured in Watts... ;)

This made me look at my Physic's book... LOL

Horsepower is a unit of power. 1hp = 0.746 kW

I'm getting old... haha
Take the year Columbus sailed and divide it by 2 for W/hp. Thats how Ive always remembered it
 

RDavisinVA

Technical Excellence Contributor
I don't think how you measure power has any relevance other than defining the "ruler" you use to evaluate and compare it.
 

RDavisinVA

Technical Excellence Contributor
This is one of the later Chevy 250 engines with a 2 barrel integrated head manifold being prepped for an install into a 110.
The engine has the factory exhaust manifold with twin down pipes.
It originally had 2 pods on the valve cover that I removed.
This engine has 40,098 original miles and cost us $300.
We made an adapter to mount the Holley Sniper 2 GC small bore EFI.
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RDavisinVA

Technical Excellence Contributor
Daily driver 110, Chevy 250 @ 75 MPH @ 19% throttle usage.
Windows are down so sounds noisy, but not from the engine which is very quiet.
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110Mike

New member
I just got back my 110 Tithonus from Robert Davis about a week ago after he put in the Chevy 250 conversion with Sniper EFI, Power Steering, a Stumpy 380 and various other smaller parts. What a different vehicle I now have! I purchased the Tithonus last fall and quickly learned it was not going to be a daily driver (or even a part time driver) with the 2.5 diesel engine that was in it. I was like Uncle Buck when I would start up the truck and smoke would blow all throughout the neighborhood.

I did not want to spend a fortune on a new setup but also wanted a nice and reliable daily driver which was enjoyable on the highway. By no means am I a mechanic or understand when folks on here are challenging Robert with their output ratio graphs, but I can tell you my new vehicle is an absolute pleasure to drive.

I am Blown Away with how different of a vehicle my 1988 Tithonus 110 is now. It starts right up, and drives amazingly. I have taken a few videos which I am attempting to post on here but am having some difficulties with at the moment working off of the iPhone. I’ll get them posted within the next several hours.

I would be happy to answer any questions you have about the conversion specific to my vehicle - keeping in mind I am a driver and not a mechanic.

Lastly - I just want to comment on how much of a gentleman Robert was to deal with. To say he was fair, honest and responsive would be the understatement of the century. Do your own research, but for me this has been a game changer.
 

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RDavisinVA

Technical Excellence Contributor
And so the installs continue... in a LHD 90.
This one has the removable manifolds and the Holley Sniper 2GC EFI.
Notice the short down-pipe with the O2 sensor bung and the accelerator linkage bracket just rear of the Sniper.
The alternator bracket is custom that repositions the alternator to the right to avoid the LHD steering box.
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RDavisinVA

Technical Excellence Contributor
The prototype accelerator cable bracket is completed for the Holley Sniper 2GC.
The machine shop is currently manufacturing a batch of them.
When you purchase a Chevy 250 engine conversion kit, the accelerator cable bracket will be included.
Those of you that want the bracket can send me a PM or email and I'll let you know the cost.
This bracket does not fit a carburetor.
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RDavisinVA

Technical Excellence Contributor
Working on AC install and other upgrades.
First step was to pressure wash and paint the Chevy 250 engine.
This was the dirty prototype engine first seen all the way back in post 2 and again in posts 6 and 23 when the kit was under development.
The radiator overflow tank will also have to have a new paint job.

Next the 220 AMP alternator, adjustable power steering pump, and Sanden style AC compressor were bolted onto the Chevy 250 engine.
The wiring was cleaned up when the relays for the AC were installed.
Am currently working on the AC condenser mounting brackets.
Then the AC condenser with the electric pusher fan will be installed.
Hopefully the rest of the AC fittings and hose will arrive this week so I can crimp the lines and evacuate and charge the system.
The Holley Sniper controls the electric suction fan on the inside of the radiator that currently cools the engine.
The system is wired to turn on both fans to cool the engine or when the AC is switched on.
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RDavisinVA

Technical Excellence Contributor
New AC condenser is in place complete with the custom mounts and the pusher fan.
The Holley Sniper controls the electric suction fan on the inside of the radiator that currently cools the engine.
The system is wired to turn on both fans to cool the engine or when the AC is switched on.
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