Series III Re-power vs. New Head

[str8films]

I recently bought a 1973 Series III North American Regular 88. It is a great, original example that hasn't been molested or beaten on. Proper parts and attention were (mostly) applied to repairs and mods. It will be a fun project to roll along and restore. My goal isn't to necessarily keep it original or exacting to factory specs. I did that with a Series 1 107" SW restoration. I want this to be practical and dependable and build in a couple creature comforts.

With all of this in mind, my first project is either replace/rebuild the head or re-power with a 2.5L used example. It seems that there are some good, used 2.5L engines out there for sale. They rival the price of a new 8:1 2.25L head that our host sells. I'm wondering what the inherit problems are with this conversion. The added power would be nice, parts seem widely available and it stays in the Land Rover ecosystem (vs. a Chevy, Toyota or similar conversion). What am I missing? What are the caveats? Curious to hear your thoughts on the matter.

Thanks in advance.

Matthew Clark
Seattle, WA

[stomper]

Any decent machine shop can take your 7:1 head, and rebuild it to the 8:1 configuration for a little coin. Much cheaper than buying a whole new head, if yours isn’t cracked. Improving the carb, and doing a few other tweaks to the 2.25 engine is a sound investment, and will be cheaper in the long run than slapping a used 2.5 engine into the truck. I’d go that route, and if you are still unsatisfied, you can sell the 2.25 as a running and driving engine to offset the cost of converting to the 2.5.

[str8films]

"Improving the carb, and doing a few other tweaks to the 2.25 engine is a sound investment..." What's your preference or the best carb option for the 2.25? And what other tweaks are you thinking of? Ignition mods?

[stomper]

Well, people seem to like the Rochester B carb for more power. I’m in the process of fitting an SU carb to
Mine, which ACR in England feel is the best option for performance. Other tweaks: electronic ignition, 8:1 compression head, and just ensuring your engine is in good health, with good compression readings is a good place to start. The 2.25 is not a hot rod engine, but ensuring it is in a healthy state and giving you all 68 or a few more ponies is always an impressive improvement.

[68Beastrover]

I just installed an EFI unit in my SIII 88" 2.25l. Now it starts in the cold and doesn't stink like partially burned gas. I still need to stuff some intake plumbing in for a K&N so I can enjoy the power increase. I ran it for a couple days without a filter and got spoiled but had to plumb it to the original air bath for an off-road confidence ride. So far I'm quite happy with it.

...now what to do with the IIB...

Steve

[str8films]

I just installed an EFI unit in my SIII 88" 2.25l. Now it starts in the cold and doesn't stink like partially burned gas. I still need to stuff some intake plumbing in for a K&N so I can enjoy the power increase.

Where'd you source the EFI from? Sounds interesting. And for the Rochester B carbs, where are people sourcing those from? And where are folks finding adapter kits for the to mount to the 2.25l intake?

I looked at the ACR site. Nice stuff, but probably too expensive for this project.

Last Question (for now): Is there a white paper or are there specs somewhere for the machining plan to skim the head to make it 8:1?

Thanks for the help.

[o2batsea]

Let's not start this war all over again but the oil bath filter flows just fine for this engine

[68Beastrover]

http://www.hamiltonfuelinjection.com/

We went back and forth shipping each other parts and adapters to make the final kit. It works great. As for the oil bath filter...I have adequate power and they are fantastic units, if I can source a larger one I will use it. It was all the air I needed to feed a 2.25 up here with a Zenith. When fitting the EFI, I removed the phenolic block and the steel collar held within leaving a somewhat larger intake diameter and the EFI unit is even a bit bigger than that. I live where the valley floors are at 4000'msl and there is nowhere to go but up so any power increase is appreciated. I drove this thing for two weeks without any filter before adapting to the original oil bath and there is a noticeable power difference when really leaning on it.

I don't know anything about the Rochester.

Call Rovers North, an auto machine shop or ask Dr. Google about the head skimming. It is probably a simple math problem. I had one done years ago and it was no big deal.

V/r
Steve