Has anyone heard of doing this.

[mytight95]

I have had a comversation with a guy at Panhandle Performance, and i was told something interesting. I said that i was thinking of going with the gt-40P heads, and i would like to keep the cam that is in the car. But i was wondering if i should port the exhaust of the heads. As i think from what i have read need a little help on the exhaust, most people use a split duration cam, but i have an E and it has the same on intake/exhaust.

This leads me to my question. They said to leave my cam in there, use a 1.6rr on the intake valve, and use a 1.7rr on the exhaust. As far as i know, this sounds like a good idea. Theoretically i guess it would work. What would the reliability, and any other issues be by doing this.


Everyone chime in

jason

 

[Rootus]

I've never heard of doing that. But I can't think of any reason it wouldn't work... just a little added cost to get the different ratio rockers. Do it and let us know what happens!

 

[swingline]

Never heard of such a thing. Doesn't mean it won't work. Try it and tell us how it goes.

 

[RIO5.0]

Iv'e read of that set-up being used before...I believe Thumper mentioned once also in an email..He might be able to shed some light on it...Makes sense to me, the theory behind it...

 

[final5-0]

That one has been around for years.

I thought about trying it when I was running ported E7's.

Did not try it cause I knew I was going for Aluminum heads and wanted to run stud rr's.

Later
Grady

 

[mytight95]

if i go with p's without a custom cam, i will run this method. or i may even run it like that until i get a cam. I have had my extra upper intake cut, so that i can port it,(or try) it was cut about 2 inches from the Plenum part, i would take pics but i didn't take the camera to my buds house, which is where i am gonna try and port, he has all the air tools etc. If anyone has tips on how exactly to port it let me know, i plan on taking a long shaft carbide and just wollering out all the runners, then i will send my lower back to Tom for some extra work.


jason

 

[baglock1]

Just keep in mind that it won't do anything for the duration. All it will do is simulate added lift on the exhaust lobes which will promote a greater rate of flow in the same amount of time.

 

[94CobraPace]

I have heard about this for for a long time. An old hot rodders trick. Hot Rod or Car Craft (forgot which) magazine has done testing on doing this before and got higher hp numbers. If you have 2 sets of rockers or can get them cheap, go for it.

 

[tcmustang]

Just to add to this...PanHandel built me a 408 complete moter a few years ago, w/ an ATI prochargerD1 They had a lot of fresh new-to -me ideas. They have a great wealth of knowledge down there, my car, an 89 went a 6.21 at 114 mph in the 8th mile the very firt time down the track. Later it ran a 9:45 in the 1/4 mile. they used a split rocker system on my car also. the only prob. I had was holding on to that car.

 

[tmoss]

The P head flow increases about 4cfm between .400" lift and .500" lift and maybe less after that. How much good will the extra lift do? It'a GREAT head for flow bwteen .200" and .400" where it maxes out flow wise.

 

[thumper460]

Actually it is an OLD trick that the circle trackers have been using for years and years... The chevy uses a 1.5 rocker and they will install the 1.6s on the intake or exhaust depending on where they feel they need more valve lift ( most circle tracker are hung up on lots of rules!!) Nothing wrong with doing it!! Just bounce the cost of rockers vs the cam change??? Most Ford guys just buy the correct cam for thier application... it hasnt been recient ( the early 90s) that the 5.0s have got into switching rocker ratios... and it IS always BEST to keep 1.6s and then get the cam you want!! bumping rocker ratios is a crutch... it works... but a crutch!! cool??

Just me..........................

Thumper

 

[mytight95]

cool thanks guys, i guess i will have to do as mentioned and weigh the cost of the rockers versus the cam swap. If i do a cam though i will most likely get a custom cam.

Does this kind of combo, with a custom cam, have the potential to net me low 13's with poor driving. P.s. i know about the headers and plan on going with the ford ones

 

[wytstang]

It's been a while since i was told this but if i remember correctly if your N/A you can use a larger rockers on exhaust side to evacuate the cylinders better, if using a power adder like NOS you use a larger rocker on the intake side to fill the cylinders more.