Twogunsblazin

I was told today that if I wanted to swap out my 2v heads with 4v cobra heads on my 03 GT I would need a new block to go with it?? I dont know if this is true or not because the guy I heard it from isnt the most experienced mechanic, but then again neither am I [&:]. If anyone could give me some answers it would be greatly appreciated.

NeoTokyo

You wont need a new block, just all the timing parts, chaings, timing cover.
I think some of the stuff on your SOHC can be re-used.

Basicly compair the engines, check part numbers for everything and start the swap. Work on it slow and go easy.

if you are realy afraid of doing this then I have a solution for you that you might be interested in, if your not interested in buying a block then dont both reading the next part.

I have a 2003 Mach1 shortblock with 0 miles on it for sale. It has all the timing components that you will need along with the cover and dampner and so forth. Its not a forged block but these are good for 650rwhp on blown applications.

I can even include a wiring harness and starter with starter harness. I am getting pictures developed of it right now. You will only need to provide the heads and intake and accessories/brackets.

There are a couple other guys interested in it too right now waiting on the pictures. Basicly who gets me the most money first gets it. Its at $1500 for everything.

na svt

The 4v heads will bolt onto the 2v engine but the compression will be 1 point lower than with 2v heads.

contentsunderpressur

+1 The swap will be more trouble than it's worth and the compression drop will actually take power from you. The easier, cheaper thing to do is get a set of patriot performance heads that have been cnc ported and you'll gain some hp. The patriots flow just as good as a stock set of cobra heads without the headack. Plus you have to change out your exhaust manifolds and midpipe to use the cobra heads and I think you'll have to drill and tap some holes to get all of your accessories to bolt up.

Twogunsblazin

What I had planned on doing was buying a set of bare heads, and slowly building them up, adding a nice cam, and putting a little extra money into them until i actually have the time to install them on the car.

silverstang1996

you do know, you will be adding 4 cams, not just one?

NeoTokyo

Anothing that you probably wont be happy with is that your GT block is an iron block, aluminum is the best way to go for a 4V

2000GT4.6

You could do all that (headwork, cams, etc etc) and spend a boatload and a half (cams alone are a grand) or just upgrade what you have.

For the same price you could do ALOT with alot less stress and have a faster car...

contentsunderpressur

If you have to have the four valve heads then go for it. The cams alone are over 1000 dollars and you'll need new exhaust and the cobra intake as the gt intake won't work. It would probably be cheaper and easier to put a whole cobra engine in there.

Twogunsblazin

Ive already got some small stuff done, CAI, o/r xpipe, mufflers, and i really want some new cams. I know a guy whos got some comp cams, and I cant get over the sound of those things.