muggsy

Hey guys,

Brand new to this forum and just picked up my 67 GTX after trading my 67 Mustang...my GTX is a matching numbers 440 w/727 trans and 3.23 gears....any quick options to get added HP. I know its a newbie question, but I know a fair amount about engine building but not Mopars. with 14 in wheels, will changing rear end gears kill any highway driving? I also have stock intake and carb...don;t want to go too radical beacuse its so original, but any suggestions would be great!

Thanks!

Mark

challenger

If you want to keep it sort of original just go with a 1" carb spacer and maybe look into upgrading the valves and port and polish , and headers would be a plus with a good flowing exhaust system as the gearing it should be ok with the 3.23 and Welcome to the forums and also lets see some pic's if you get a chance of the car

BuckNeccid

Keep the exhaust crossover even if you put headers on it, it does help with the torque. I agree with Challenger on what he's said. Just to free up some horsepower you already have and still stay hidden and not change the stock appearance, think about some roller rockers.

67 GTX

hey, i have the same car, except its a 4 speed
you can put headers on

plymouthrr1985

Good job coming over to the mopar camp!!!! Maybe a cam change to go along with the exahust upgrade would be a good i dea too, but nothing too radical.

muggsy

would you do an intake and carb swap from the original? If so, what is best for these cars? I know the small block Fors like the back of my hand, but these are new to me...BTW: what size (CFM) 4 barrel carb was stock on a 67 GTX?

67 GTX

an 800 CFM AFB was stock

plymouthrr1985

Edlebrock makes a carb cam and intake pakage that is matched to each other that would work well on the street if you want to go that route. If you swap i would save all the original parts so you can put them back later if you plan to sell.

67 GTX

you cant get too radical though on the intake manifold, because with the air cleaner on, it sits really close to the hood stock, so if you mess with it....

67 GTX

i think I know what you want
these cars are rare, so you want to get more power without making it shown, right?

muggsy

yes, and I don't want to potentially harm the original motor. Take for example the Mustang I just sold to buy this GTX. It came with the original 289. I wanted to build it, took it apart and realized the motor, which ran "fine" but slow, was overbored .060. If you know anything about small block Fords, max bore is .030. Tearing down the motor was the end of it and I had to buy a crate 302. Not such a big deal in a 200 HP Mustang, not really a "special" car, but I think I'd feel REALLY bad if I "F'd" up an original 440...

So, long story short, I want to add HP and keep it looking stock, and need to know which changes require new internals as well. Does the package ChallengeMe suggested require new pistons, rings, rods, crank, or is it safe in these motors to just build top end? Like I said, I really only know SBF and their stock motors had weak internals....can the 440 handle the added HP of the heads and intake and headers? You know the old saying: "Horsepower is cheap, strength is expensive"...

Maybe I should just build a 440 and take out this motor and store it in my garage, but that is awfully expensive. I like the sound of Stealth heads, intake and headers for $1200 if that is a safe build...

thanks for the input

Erikthegoalie

subscribing...also rebuilding a 440 in my Dads 67 GTX...

67 GTX

which way did you end up going?

muggsy

nothing yet....leaning toward new exhaust and leaving the engine stock...but I know I woun't be able to fight off the urge to beef up the HP. My Mustang had 325HP to the rear wheels and I miss that feeling. I guess I underestimated how important that was toward making it a fun ride. I really don;t want to mess with this car though....really torn at this point.

67 GTX

new rating, the car has around 325 at rear wheels, thats stock
you can do all sorts of things to get it higher
increase timing for example

muggsy

Would a good head and intake port and polish get me much here? If so, approximately how much should this cost and what is the HP gain, considering I'd probably do headers at the same time?

67 GTX

you will get more horsepower, but your not gonna race the car are you?

muggsy

definitely not racing, just looking for a bit more HP.

67 GTX

how's it going with the GTX?

Erikthegoalie

hey guys, just dropping a line...took the 440 out, it is worn...

Going to the machine shop Wednesday AM to get a quote on a build...

Probably going to reuse the stock crank (since it is forged), stock rods (since they are plenty for this build), and new forged pistons since the bores need to be honed anyway! We're thinking about punching them out to .040 over.

The deck needs to be resurfaced as well as I think a head lifted as some point causing a lot of coolant to leak from under the heads...who knows what the heat did to the deck, or heads!

I am still trying to convince my dad to go with the 440Source stealth heads instead of rebuilding the 915 cast iron heads...I am sure refreshing the heads will be the same as buying a nice set of lightweight aluminum heads....we will see!

Anyone wanna see pics?

erik

67 GTX

i''d like to see some pics
the 915 heads are steal, not iron
erikthegoalie, where are you located?

Erikthegoalie

Hey boss...

The stock heads are cast iron aren't they? I was not aware that steel was even used in manufacturing...these are the stock heads that came on the 440 HP RB motors...(accorinding to teh part number)

You sure about that? They sure look like CI, lol.

I am located just north of Ft. Lauderdale, FL, in a town called Margate.

Ill get some pics up soon!

THANKS

67 GTX

yep, im pretty sure
67 was the last year for the 915 heads, the next year they switched heads and pistons in the 440, and the 915 heads went to the 383

Erikthegoalie

yeah, the part # on these heads is: 2780915-3 (stamped on the intake runner)

I am 99.9% sure the material is iron...I know they are some heavy SOB's lol! Bout 80 lbs a head.

Let me go get some shots!

erik

Erikthegoalie

Below are some recent pics of extraction, and breakdown. I had to set up a makeshift shop in my garage cause my shop is full of customer cars, but, it works!

Any questions feel free to ask!

Erik

67 GTX

thats not the original engine right?

Erikthegoalie

We're not sure. It is the correct motor, if that is what you were asking- that came in the 67 GTX 440/727 cars. We bought the car a few years ago from Southern Motors in Michigan.

It appears that the car was restored in and out pretty well, but some things were done halfassed- I have to admit. So, I am slowly going through and refreshing everything, and getting things looking pretty.

We are not building this thing to be "numbers matching," concorse car, blablabla, we just want a nice street rod that turns heads and rumbles!

Erik

67 GTX

are you gonna paint the engine the correct mopar blue?
i found a site about the heads, and it says that they are steel
here's the link: http://www.moparmusclemagazine.com/t...ory_parts.html

challenger

the heads are 383/440 1967 with 2.08 and 1.60 with the # you gave and if you want to find out more on your engine you can check out these sites Mopar VIN Decoder Mopar Muscle Cars Mopar Casting Numbers - MyMopar.com - Mopar Part Numners Mopar Codes - MyMopar.com - Mopar Part Numbers