1980 4.2 V8 (255) Free cheap hp ideas?

89Stang · Sep 22, 2008

Anyone wrenched on one of these things? Planning on picking this thing up and tossing in a mild 306 over the winter. But its a 4.2L 120hp V8 Auto... from what ive read this thing is slower than my old 2.3L auto coupe. Thats just as hell to me. Please tell me theres some free/cheap mods I can do so Im not embarassed by 2.3L mustangs with blown headgaskets beating me!!! Also as Im new to the 4 eye crowd whats needed to bring these things upto at least 87 standards? (wont be going efi will be staying carbed) By the way this will be my 7th mustang lol

93 LX · Sep 22, 2008

no performance parts for the 255 engine. Junk it and throw in a 5.0 or 5.8.

89Stang · Sep 22, 2008

93 LX said:
no performance parts for the 255 engine. Junk it and throw in a 5.0 or 5.8.

thats the idea. But would be driving while picking up the parts so there has to be something I can rip off and keep in the car to throw at a honda.

85_SS_302_Coupe · Sep 23, 2008

I don't think i'd trust that engine as a boat anchor. In fact i'd rather have a stock NA 2.3 than a 255. The most you might do to it is put a small 4 barrel on it but i wouldn't invest any money in it.

As for "bringing up 4 eye cars to at least '87 standards", the '85 HO will run just as hard as any '87+, and the cars typically weighed a couple hundred pounds lighter so in my experience there's little if any loss in performance. Get yourself some headers and a decent intake and Holley and you'll run with the best of the stock 302s. Get some GT40p's and a good cam and you'll walk on any stock Mustang except for the DOHC Cobras.

89Stang · Sep 23, 2008

I know the 85s ran good then I thought the 86s were down some then the 87s were back up a bit.

But as far as 87+ standards I know a lot of the 4 eye guys hate it but I mean dash front clip and maybe taillights (though the project 81 thats up looks like the early 80s taillights were different in a few ways so that might be a pain)

I dont really want to invest any money at all in the 255. Was just curious if theres any free **** I can do to get upto at least 125hp

93 LX · Sep 23, 2008

Well I think the 255 has a variable venturi carb. I had a friend who had a "cobra 2" with that carb in a 5.0L. We replaced it with a Weber/Holley 5200 and that engine woke up. Still wasnt quicker than my stock 82 Capri RS 5.0 HO but it did make it a race! LOL

89Stang · Sep 23, 2008

I read the heads are just beyond horrible on this thing. So not sure how much can be gained but Im sure there has to be some garbage I can rip off of it just to make it run better

watch this thing also have some retarded rearend gearing like 2.50 or something....

mavmavv · Sep 23, 2008

Lol, scrap that thing. You can get stock 5.0s almost free nowadays.

bgjohnson · Sep 23, 2008

I read of a guy that built one up just to do it, kinda funny to watch the whole process. Wasn't fast by any means but it wasn't as much of a dog.

89Stang · Sep 23, 2008

Trust me I plan on scraping the 255 thats in it. Should be pretty easy to swap in a 302!

Red · Sep 24, 2008

89Stang said:
But as far as 87+ standards I know a lot of the 4 eye guys hate it but I mean dash front clip and maybe taillights (though the project 81 thats up looks like the early 80s taillights were different in a few ways so that might be a pain)

shame on you for wanting to disturb a 4-eye like that!

SVT32VDOHC · Sep 24, 2008

That's what was in my 81 notch! OMG! Couldn't even spin the tires in the gravel!

Junk that POS!

mavmavv · Sep 24, 2008

Reminds me of the junk 250CI I6 I had in my first truck. It was a 1980 Chevy C10, I think it was rated at something like 130HP, It was such a slug in that Fullsize truck. All the smog provisions and horrible head on it really killed any flow.

Its cool to see those engines boosted though, they make some good numbers with a decent head and intake/exhaust setup.

57fairlane · Sep 24, 2008

I want the crank out of it when you are done . . .

the heads have 289 combustion chambers, pedestal rockers, and the smallest intake ports I have seen.

You could port it out. That was actually the first set of ford heads I ported on and the exhaust you can get awfully similar to a ported e7 (other than the valve size).

The intake will take quite awhile as it is shaped like a small egg and the runners seem long for whatever reason. The valves are tiny.

I doubt there are truly any "free" mods to this thing unless you have a bunch of stuff laying around. Maybe bump the timing a little . . .

You could get some roller rockers or headers/exhaust as that would fit a normal 5.0.

Throw an 8.8 under there with more gear . . .

89Stang · Sep 26, 2008

I know people dont like it when 4 eyes are messed with but I have my ideas for this thing.

SVT32 on your project you said the taillights were different on the 80-81s than the newer fox taillights? Also how much would you charge to do the Sn95 dash and center console?

As far as hp I guess right off the bat I will rip off as much emissions crap as possible. Exhaust was planned for the new engine. But was planning long tubes. That might be a bit overkill on a 255 but who knows maybe I will try. But a 302/306/308 is planned.

2000GTdriver · Sep 26, 2008

89Stang said:
I read the heads are just beyond horrible on this thing. So not sure how much can be gained but Im sure there has to be some garbage I can rip off of it just to make it run better

watch this thing also have some retarded rearend gearing like 2.50 or something....

Worse than that-1980-81 cars that came with the 255 and auto had a 2.26:1 gear ratio with a 7.5 inch rear. Ignore the weak engine and put in a decent 8.8 you will be happy later.

89Stang · Sep 26, 2008

honestly Im not looking to make this thing a screamer. So the plan is a mild 302 based engine a 5 spd and good highway gearing (will just go with a 2.73 8.8)

slow84lx · Sep 26, 2008

89Stang said:
I know the 85s ran good then I thought the 86s were down some then the 87s were back up a bit.

But as far as 87+ standards I know a lot of the 4 eye guys hate it but I mean dash front clip and maybe taillights (though the project 81 thats up looks like the early 80s taillights were different in a few ways so that might be a pain)

I dont really want to invest any money at all in the 255. Was just curious if theres any free **** I can do to get upto at least 125hp

You bring the standards way down by switching out the front end, not up. Same for the interior. If you don't like your interior there were many options available that are easily switched out.

I know several guys with '86's that run really well. The '86's do get a bad rap from many for the lack of valve reliefs in the pistons limiting camshaft and valve selections.

You might get better performance with an early set of 260 heads but it wouldn't be enough to be worth the cost. Just get a 5.0 and save your money for that.

If you really want a 5.0 '87-up car you would really be better off by selling what you have and getting a later model car. You will spend a lot less $$$ by doing so......and be happy........and not be hacking up a 4-eye car in the process.

89Stang · Sep 26, 2008

in all honesty theres some unique touches I want to add that are classy and subtle that I would have to do to an 87-93 plus the price of this car is just too good. So to get an 87-93 would run a similar amount of money plus more money for the intial price of the 87-93. As far as the interior I just dont like the 4 eye interiors. Driven a few GTs and a Few SVO's and while I thought the seats looked good I didnt like the way it felt. Mainly im just curious how hard it is to update to the 9004 headlight style of the 87-93 models. Also interested in how hard it is to wire either the sn95 interior or the 87-93 interior into the 4 eye. As well as the 87-93 tail lights.

Power wise it will just be a mild 302 based engine with most likely a 2.73 8.8 or a 3.08 rear. I liked the way my 89 gt ran with the highway gears. With a cooling fan and cold air intake base timing full tank of full every option that car ran a 14.42 at 98mph with a 2.21 60ft. I want to be 13's and since this is a lighter car that shouldnt be a problem.

cenok is family · Sep 26, 2008

aren't the v6 K members different than the v8? when you switch over, you're going to have to switch that as well.

1980 4.2 V8 (255) Free cheap hp ideas?

89Stang

93 LX

89Stang

85_SS_302_Coupe

it sucks (I know) to be on the receiving end

89Stang

93 LX

89Stang

mavmavv

New Member

bgjohnson

89Stang

Red

SVT32VDOHC

waiting for the next hack atta

mavmavv

New Member

57fairlane

New Member

89Stang

2000GTdriver

Member

89Stang

slow84lx

clean it good before insertion

89Stang

cenok is family

1980 4.2 V8 (255) Free cheap hp ideas?

it sucks (I know) to be on the receiving end

New Member

waiting for the next hack atta

New Member

New Member

Member

clean it good before insertion

Privacy & Transparency

Privacy & Transparency