255 V8....Anyone familiar with those?

[fordnmerc]

I am considering a 1982 Panther with that engine. I've been doing some reading about how the engine was derived from the 302.

I take it that the 255 in the Panthers had a variable venturi carb.

We had a 1982 LTD with the 302 and a variable venturi carburetor and that carb was absolute crap. We should have replaced that with a different carb.

But was it 'the luck of the draw'? Did we just get a bad one? 'Supposedly' there were 2....the 2700 and the 7200.People have said that the 7200 was the lousy one. Any truth to that?

Thanks!

[gadget73]

a gutless engine with a moody pain in the ass carb. Replace both in one go with stuff that doesn't suck and you're good.

[Kodachrome Wolf]

Supposedly the 255 could manage decent fuel economy numbers. Reports had them at around 27 or so on the highway. However, the 255 was seriously under powered considering curb weight of those cars. It made 115 HP and 205 FT-LBS. Considering modern speeds on highways, you'd have trouble if you needed to accelerate quickly if you were above 65 MPH.

Outside of subpar power output, the Variable Venturi carburetor could be a trouble spot. When tuned correctly, they worked great. If it's out of whack, you'll get worse performance and poor fuel economy. You could probably replace it with a standard carburetor, preferably whatever was the one people like using on the 302s to replace the VVs. IIRC, people said to use the Holley 2150 for a replacement.

If you could get everything running good, you would have a good back roads cruiser. It would be slow, but would probably find a sweet spot doing 55 to 60 MPH.

[Mainemantom]

I had one in my old 82 MGM. 212,000 miles on original motor. Good gas mileage. Under powered but it handled climbing the mountains. VV carb. was ok until a mechanic messed with the internal adjustments. It never ran well again.
Many people don't like the 255. Mine was good. I do prefer the 302. Just like anything else,if maintained and runs well, it could be decent.

[fordnmerc]

Many Thanks for the replies.

[mcninetyone]

I would consider the cost of replacing both, the 255 and the VV into the price of the car. You would do much better with a 302/351W and a real carb.

[Tiggie]

IIRC 255 valves were smaller than the already small smog era 302/351 heads. They will get you around but not quickly.

All VV panthers were the 7200 with "computer controls". 2700 was non computer assisted used in other fun things like Grenada's. 7200 runs without the computer installed - rich - but it runs. Tie the choke open with wire if it ever causes problems and they can be very usable. I did that to mine on my old 82. The cold enrichment rod wears and doesn't do its job as it should. It wasn't good at WOT but always started even at zero degrees. Idled at like 200rpm and sounded like a two cylinder John Deere when it was that cold. Delivered same or better mpg on highway as SEFI as long as that choke was open.

[dd345]

My 91 had a Variable Venturi carburetor, I put the older style 2bbl and duraspark 2 off of a 70's f100. I Would vote to get a roller 5.0 out of a explorer with the gt40 heads, put on a motorcraft 2150 with duraspark 2, and enjoy the car.

[DerekTheGreat]

I have no experience with a 255. However, I find the LoPo 302 to be gutless and BARELY adequate in any gear other than 1st. At speeds greater than 60mph it sucks, could only imagine how a 255 would fair in these boats, especially with it's peanut cam & carburetor, even if you did swap it out for one without the VV funkyness.

[knucklehead0202]

I have no experience with a 255. However, I find the LoPo 302 to be gutless and BARELY adequate in any gear other than 1st. At speeds greater than 60mph it sucks, could only imagine how a 255 would fair in these boats, especially with it's peanut cam & carburetor, even if you did swap it out for one without the VV funkyness.

^^^This. The lopo 5.0 is depressing enough as it is. Chop a bunch of power off that and you have a Geo that weighs 2 tons. Dump that boat anchor and put a good engine with EFI or a real carb and never look back.

[Grand Marquis GT]

I think the 255 was in response to GM putting V6s in the full size cars.

[gadget73]

"Hey look, we can put in a shitty motor too."

Some response. The 4.3 I think made more power than the 255. The Buick 231 though, good god what a turd. The 307 was horrible enough, but it was a rocket compared to the V6.

[Brown_Muscle]

I'd love to see a decent 255 hi performance build, for both power and economy. Bet it would do OK if done right, but be hella-expensive

[Tiggie]

The small bores limit your ability to run heads with larger valves so that kind of kills the hi po build.

[gadget73]

Multiport converted 255 anyone?


Not worth it though TBH. Teeny displacement doesn't automatically make better fuel economy, which is ultimately why I think that engine was killed off. I know a guy who did a non-stock 351 swap into a Mark VII and picked up several MPG along with about 100 hp over the stock 302.