Cam Selection, please advise.....

[85 Coupe 5.0]

Comp Says 262's won't work!!

Well, once again, the need to go faster has tempted me again........

I have decided to get a set of cams for the car, but am unsure of what to go with. I would like to go with Comp as they have a decent set of cams available and VT seems a bit high, although possibly better. Anyhow, I have the mods done as follows:

'96 GT

Stock '96 short block
'00 Windsor PI Heads+cam+intake conversion
SCT Tuner
3.73's
J-MOD to the 4R70W
Off-Road H-pipe+flows

I have been looking at a set of Comp 270's, but after calling Comp they recommend the non-pi 268's. The reasoning is that with the PI heads on my motor I will have PTV clearence problems with the 270's and they say go no bigger than .500 lift with my setup. WTF? The factory cams I have now are .510/.530 and i'm not having problems.

I have a set of 262's lined out that I can get cheap also. Why is comp recommending the NON-PI cams for me?

Can someone please help, i'm very confused, did I just talk to a bad tech when I called comp?

 

[85 Coupe 5.0]

anyone been down this road before?

 

[Skidzz]

I think you talked to a bad tech. Look at my mods. I have the 262's with the PI swap and I make 265rwhp. I have no negative issues. If you can get 262's for a good price, go for it.

 

[85 Coupe 5.0]

that's kinda what I thought, but I keep getting mixed opinions reading the forums, but the majority says it should be fine, and obviously it works as you are running them with a PI swap. I might give the comp tech line another call, maybe get another tech and see what happens.

Also, did you notice a big gain with the cams? how about idle, does it have a noticeable lope? Thanks again skidzz!

 

[85 Coupe 5.0]

anyone else running these cams with the PI swap setup?

 

[four six]

Im running VT stage 1 cams. I made 251rwhp w/o TB, plenum, and LTs

 

[COramprat]

I've got the 262's in NPI heads. Lope isn't too noticeable but it is there. Mine dyno'd at 230HP on a Mustang dyno.

Check my garage in sig for other mods and quarter times.

Comp probably didn't understand you have PI heads is the reason why they recommend the NPI cams. The lift on those is less than the PI's.

 

[85 Coupe 5.0]

I've got the 262's in NPI heads. Lope isn't too noticeable but it is there. Mine dyno'd at 230HP on a Mustang dyno.

Check my garage in sig for other mods and quarter times.

Comp probably didn't understand you have PI heads is the reason why they recommend the NPI cams. The lift on those is less than the PI's.

Maybe, but I told the guy 2 times I had the PI conversion. He told me the reason that I couldn't run the PI cams was because it would have PTV issues if I go over .500 lift, but yet the stockers I have now are suppossedly .510/.530.

I'm so confused, is anyone else running Comps on PI's with an NPI block/pistons?

 

[paintballtommy]

piston to valve clearance has alot more to it than jsut gross lift at the valve. figures such as duration and overlap also apply. when the valve is completely open the piston is more or less probably furthest way from the valve. whichever way you decide to go deffinitely check clearances before firign the motor up. i believe proper clearances for intake and exhaust valves is something along the lines of 80 thousandths or more. correct me if im wrong please

 

[85 Coupe 5.0]

well, i know it's not a good idea, but I was trying to aviod having to check clearance and degree the cams. I'd really like to get some real world examples that the 262's will work with my setup without degreeing or anything. was hoping to find some people that have already done this and not had a prob.

Really not looking forward to pulling the motor and taking it apart, although it would be a good idea that way I know for sure it's going to work.

 

[85 Coupe 5.0]

well, i'm going to try calling comp again, noting some of the points you have set aside.

I belive that I will be o.k. with the smaller PI cam that comp offers, i believe it's the 268. Are there any others running this cam with a stock '96 NPI block? and if so, any problems?

 

[96GTstang46]

Im really glad that you asked this question cuz i have done the PI head swap as well.. read my sign. for more upgrades..
Umm i wanted to get some more power out of mine as well but i was told that the 262's were too close as well.. there again i could have had bad advise just like you did. (85 Coupe 5.0) But i need to get my car Dyno-ed tuned but if you guys can let me know more about cams that would be great. I.E Brand, lift, and what not.

Cool well thanks again :SNSign:

When in doubt... a** end out... lol

 

[85 Coupe 5.0]

That's two now that comp says can't run 262's, Skidzz, you have the 262's with a PI swap and aren't having problems?? Anyone else been down this road? If I can just get a few people that are doing it with no probs i'm just going to say screw it and run them, maybe comp is wrong?

 

[COramprat]

That's two now that comp says can't run 262's, Skidzz, you have the 262's with a PI swap and aren't having problems?? Anyone else been down this road? If I can just get a few people that are doing it with no probs i'm just going to say screw it and run them, maybe comp is wrong?

I thought the first guy said 262's were OK or did I read it wrong?

I'd be very careful in taking advise here and going against what a company that has spent some money on R&D would have to say. There is a reason they are giving you that advise. Go against it and you may wind up wishing you hadn't.

My argument would be that you will not see that great of a gain between 262's and 268's. Maybe 7-10 HP.

 

[85 Coupe 5.0]

I thought the first guy said 262's were OK or did I read it wrong?

I'd be very careful in taking advise here and going against what a company that has spent some money on R&D would have to say. There is a reason they are giving you that advise. Go against it and you may wind up wishing you hadn't.

My argument would be that you will not see that great of a gain between 262's and 268's. Maybe 7-10 HP.

that's kinda what I was thinking also, I mean, it's kinda weird that two people have called comp and got the same answer. Hopefully Skidzz will ring us back here and give us a little insight, so far he's the only one running the cams with a NPI shortblock.

 

[Skidzz]

Sorry it took me so long to check this post again. I have no issues at all with my 262's. Not only is it ok to run the 262's, but also, 262's were the cams that Modular Depot RECOMMENDED when we were setting up the appointment for the swap and tune. I recommend getting valve springs with them also, even though people will tell you they aren't necessary. It's good insurance and only adds about $150. I also recommend adjustable cam gears to degree them. I didn't do that and I wish I had. The power increase from NPI to PI/262's is amazing. The lope is pretty nice once the car reaches operating temperature and idles down under 1000 rpms. It's also nice being able to finally give LS1's a run for their money (even though I still usually lose ) Here are a couple of short videos of my car after the install.

Idle and Rev

2nd gear punch


Edit: Oh, after reading your post again, I think that maybe Comp misunderstood you. If they are recommending NPI cams, then they probably missed the part about you having PI heads. Talk to them again and make it clear that you are also doing the PI head swap, and I'm sure they'll tell you that 262's are fine.

 

[85 Coupe 5.0]

thanks Skidzz, I was hoping you'd make it back! So, there we have it, finally some hard evidence. I know someone else posted here about running VT's with no problems, and that's cool, but I was really wanting someone to be running Comps and not have a problem.

So, looks like i'm going to get the 262's after all!