Gt40 non p head swap

Tristatev8 · October 25th, 2011, 03:39 PM

Ok guys ii have a 70 coupe with a 90 gt motor in it converted to cardurator. I just pickef up a set of gt 40 non p heads off a 97 explorer. Are these a direct bolt on or what will I need? New rockers? Pushrods? Ect. im new at this head swap part of the building proocess.

dirty_d · October 25th, 2011, 03:53 PM

I just installed P's, everything should just bolt on for you. I'm not sure but I think you need new valves springs. You should be able to get away with using your mustang's springs on the gt40 heads if the heights are the same.

Tristatev8 · October 25th, 2011, 04:17 PM

So push rods will line up and can I use my stock rocker arms or do I need 1.6 or 1.7 rr since im gonna get some prolly later on if I dnt have to right now

ryanw · October 25th, 2011, 05:18 PM

You should still check push rod length and piston to valve clearance. If you buy the right size after market cam later on down the line then you shouldn't need 1.7rr. Going with 1.7rr is really only needed if your trying to get more lift out of your existing cam. That's how I understand it any ways. If I'm wrong then some one correct me

Tristatev8 · October 25th, 2011, 06:28 PM

how do i check piston to valve clearance? im running stock cam and dont plan on upgrading it anytime soon as i plan on doing a bbf swap in the near future!
i dont want to change springs if i dont have to. i ust plan on gasket matching and having a valve job done and would like to bolt them on a stock bottom end.

can i use my e7 rocker arms or do i need 1.6rr?

Tristatev8 · October 26th, 2011, 01:06 AM

Bump someone help plz

dirty_d · October 26th, 2011, 09:09 AM

you can use the same rockers. The thing with the springs is I think the HO cam is more aggressive than the stock springs on the gt40 heads were made for, but if you use your stock HO springs then you know they will be fine. That's if they have the same installed height etc, which I'm pretty sure they do. You definitely shouldn't have any piston to valve problems with the stock cam and rockers or even 1.7 rockers.

Tristatev8 · October 26th, 2011, 10:26 AM

So now my question would be will my stock pushrods match up?

dirty_d · October 26th, 2011, 10:42 AM

yea they will always line up, do you mean too long or short? They should be perfect unless the heads were milled or you have a cam with a different sized base circle or anything that would move them up or down in relation to the valve stem.

Tristatev8 · October 26th, 2011, 12:19 PM

Yes d I mean length sry didnt specify. And stock cam. Not gonna mill the heads as they are not warped or anything jyst some gasket match porting. What springs do u suggest if I wanna go aftermarket instead of using my e7 springs

dirty_d · October 26th, 2011, 12:55 PM

if your gt40 head's springs installed heights etc are the same as the gt40p's which I think they are, then I'd go with the 44308-1 crane cams kit. I did a lot of researching for the springs to use on my heads, and those seemed to be the best from what I've read. You can use the trickflow TFS-2500100 kit too, but some people have complained about them having cheap retainers and soft locks so I went with the crane cams kit.

OZ_872 · October 26th, 2011, 01:38 PM

Pushrods should be identical, when I did my gt40p swap we measured the spring rate from the stock heads to the P's, springs were basically the same, I ran the gt40p springs shimmed with the GTP rockers (same as the stock mustang rockers anyhow)... and actually from what I've read the stock explorer/mountaineer cam is a bit more stout than the stock mustang cam, i'm not 100% on that though

October 25th, 2011, 03:39 PM	#1
Tristatev8 Newbie Join Date: Oct 2011 Posts: 9 iTrader: 0 reviews	Gt40 non p head swap Ok guys ii have a 70 coupe with a 90 gt motor in it converted to cardurator. I just pickef up a set of gt 40 non p heads off a 97 explorer. Are these a direct bolt on or what will I need? New rockers? Pushrods? Ect. im new at this head swap part of the building proocess.

October 25th, 2011, 05:18 PM	#4
ryanw I Post Entirely Way Too Much 1991 Ford Mustang GT Join Date: May 2007 Location: San Diego, California Posts: 6,063 iTrader: 0 reviews	You should still check push rod length and piston to valve clearance. If you buy the right size after market cam later on down the line then you shouldn't need 1.7rr. Going with 1.7rr is really only needed if your trying to get more lift out of your existing cam. That's how I understand it any ways. If I'm wrong then some one correct me __________________ DART 331ci stroker, AFR 185 heads, Trick Flow R intake, Accufab 70mm tb, 75mm pro m Maf, 30lb injectors, jba headers, 2 1/2" x pipe flowmaster super 10 mufflers, 255 fuel pump, 3:27 gears

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October 25th, 2011, 03:53 PM	#2
dirty_d Regular Join Date: Sep 2010 Posts: 58 iTrader: 0 reviews	I just installed P's, everything should just bolt on for you. I'm not sure but I think you need new valves springs. You should be able to get away with using your mustang's springs on the gt40 heads if the heights are the same.

October 25th, 2011, 04:17 PM	#3
Tristatev8 Newbie Join Date: Oct 2011 Posts: 9 iTrader: 0 reviews	So push rods will line up and can I use my stock rocker arms or do I need 1.6 or 1.7 rr since im gonna get some prolly later on if I dnt have to right now

October 25th, 2011, 06:28 PM	#5
Tristatev8 Newbie Join Date: Oct 2011 Posts: 9 iTrader: 0 reviews	how do i check piston to valve clearance? im running stock cam and dont plan on upgrading it anytime soon as i plan on doing a bbf swap in the near future! i dont want to change springs if i dont have to. i ust plan on gasket matching and having a valve job done and would like to bolt them on a stock bottom end. can i use my e7 rocker arms or do i need 1.6rr?

October 26th, 2011, 01:06 AM	#6
Tristatev8 Newbie Join Date: Oct 2011 Posts: 9 iTrader: 0 reviews	Bump someone help plz

October 26th, 2011, 09:09 AM	#7
dirty_d Regular Join Date: Sep 2010 Posts: 58 iTrader: 0 reviews	you can use the same rockers. The thing with the springs is I think the HO cam is more aggressive than the stock springs on the gt40 heads were made for, but if you use your stock HO springs then you know they will be fine. That's if they have the same installed height etc, which I'm pretty sure they do. You definitely shouldn't have any piston to valve problems with the stock cam and rockers or even 1.7 rockers.

October 26th, 2011, 10:26 AM	#8
Tristatev8 Newbie Join Date: Oct 2011 Posts: 9 iTrader: 0 reviews	So now my question would be will my stock pushrods match up?

October 26th, 2011, 10:42 AM	#9
dirty_d Regular Join Date: Sep 2010 Posts: 58 iTrader: 0 reviews	yea they will always line up, do you mean too long or short? They should be perfect unless the heads were milled or you have a cam with a different sized base circle or anything that would move them up or down in relation to the valve stem.

October 26th, 2011, 12:19 PM	#10
Tristatev8 Newbie Join Date: Oct 2011 Posts: 9 iTrader: 0 reviews	Yes d I mean length sry didnt specify. And stock cam. Not gonna mill the heads as they are not warped or anything jyst some gasket match porting. What springs do u suggest if I wanna go aftermarket instead of using my e7 springs

October 26th, 2011, 12:55 PM	#11
dirty_d Regular Join Date: Sep 2010 Posts: 58 iTrader: 0 reviews	if your gt40 head's springs installed heights etc are the same as the gt40p's which I think they are, then I'd go with the 44308-1 crane cams kit. I did a lot of researching for the springs to use on my heads, and those seemed to be the best from what I've read. You can use the trickflow TFS-2500100 kit too, but some people have complained about them having cheap retainers and soft locks so I went with the crane cams kit.

October 26th, 2011, 01:38 PM	#12
OZ_872 Regular Join Date: Oct 2009 Posts: 109 iTrader: 0 reviews	Pushrods should be identical, when I did my gt40p swap we measured the spring rate from the stock heads to the P's, springs were basically the same, I ran the gt40p springs shimmed with the GTP rockers (same as the stock mustang rockers anyhow)... and actually from what I've read the stock explorer/mountaineer cam is a bit more stout than the stock mustang cam, i'm not 100% on that though

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