cam and valvetrain

[tylerrocks]

Hi all, I am pretty green when it comes to matters of camshafts and valvetrain so I need a little help. Basicly I have a stock 260 V8 That I am looking to liven up a little untill I get and build my 2005 500 horse mustang. I just bought a edelbrock RPM intake and a 650 speed demon with mechanical secondaries (not installed yet) and now I am turning my attention to a cam. Like I said before I am not very educated on camshaft geometry but I do know a little. This car would be driven on street only, I would probly only rev it to 4500-5000 RPM on occasion. It has stock 3speed manual but I have a T-5 that is soon to go in. The gearing is stock 3.00:1 but will be changed to 3.73s later. The cam I'm looking at is CompCams XE274H http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=31-246-3 What do you thing about it? Any other suggestions?
My questions:
1. Do i NEED to use new lifters?
2. Do I have to replace pushrods? (I assume not)
3. I have never taken the valve covers off, but do I have need to replace any stock components (except rockers) if I use roller rockers?
4. Could I use a 1.6 Rocker? how about a 1.7?
5. Dose anything special have to be done about the distributor shaft/gear?
6. Will I need aftemarket valve springs?
7.Anything important I need to know that I didn't ask about?


Tyler

 

[tylerrocks]

ANYbody?

Tyler

 

[D.Hearne]

Seeing that 260 V8 Stangs are so rare, I strongly recommend that you leave this one be. That carb will be too much for it. Your cam choice is also way overboard as well. If anything, pull the 260, keep it intact and stored properly and get a late model roller 5.0 to replace it to play with. Better yet sell the car and get one that's already been modified.

 

[steel1212]

I'm going to have to agree with Hearne on this one. If its a matching numbers car I.E. the car came out of the factory with that motor, leave it be. If you really must have more hp then do what Hearne said and pull its, store it, and find a roller 302 or 351 and build. Just my 0.02

 

[SoCalCruising]

Ditto about storing the 260. However, if you proceed, take heed of the above advice about the carb and cam. A Performer intake and 500cfm carb would be a better match for your stated RPM limit and size motor. Yes, you will have to use new lifters and, undoubtedly, new valve springs. The heads probably still have the stock press-in studs and these should be modified for screw-in studs if you increase spring pressure and use a higher lift cam. If you use roller rockers, you'll also need hardened pushrods and guide plates. Pushrod length should be determined with an adjustable pushrod - don't assume that the old length will work with the roller rockers.

As you can see, the work and money involved to modify the 260 is more than you might have imagined. Think hard about replacing the motor with a 5.0 or maybe get a FMS crate motor. Good luck.

 

[tylerrocks]

Thanks for at least giving me SOME info SoCal, the two replies before you sound a little parental. Basicly, I INTEND to liven up the 260. I have never been that crazy about originality (Yeah, whatever but this is MY car). If I had had the chance to buy a 65-66 instead of the 64.5, I probly would have taken it. It just so happens that I came across the 64.5 when I was looking for a stang, it was in good condition, and a good deal. I knew from the get go I wanted a restomod, and dont get me wrong, it's not tacky. I have a 302 roller block that I got out of an early 90's crown vistoria that I planned on swapping in, but it just costs so much to do a buildup. The money I spend on the 260 would only get me a shortblock (if that) on the 302. My reasoning is: If I put these parts on the 260, I will still have them to put on the 302 when I build it. I am a college student so cost is a concern as I can only work in the summer months. Again I need cam suggestions if the XE274 is too big.

Tyler

 

[D.Hearne]

Ok, so my advice is too "parental", yet you say you acknowlege that XE274 is too big? Thing you don't understand about the 260 is it's bore/stroke. Bore is smaller ( 3.8 if I ain't mistaken) than the 289/302/5.0's 4.00" so you've got more to shroud the valves. They've also got smaller valves than even the stock 1.78/1.45 289/302 heads. Stroke is the same as the 289 ( 2.87) You can't swap on larger heads due to the fact that the larger valves will hit the deck. You're STILL better off doing the roller 5.0. Just go by a rebuilt short block, change the rod bolts & cam, bolt on some E7TE heads ( or whatever you can afford) and you'll end up with a stronger motor than the 260 will ever be for less money. If you're not concerned with your car's originality, sell the 260 to somebody who wants it for what it is. That in itself will go a long way toward getting what you want.

 

[tylerrocks]

Seeing that 260 V8 Stangs are so rare, I strongly recommend that you leave this one be...... If anything, pull the 260, keep it intact and stored properly and get a late model roller 5.0 to replace it to play with. Better yet sell the car and get one that's already been modified.

These were the statments that I was refering to as parental. As I recall, I made it quite clear in my original post that I had very little knowlage on camshafts and valvetrain (hence the post's main pourpose) I was merely asking for suggestions on a cam (got any?). I am aware of the Bore/Stroke of the 260 I had not planned on putting diffrent heads on but good to know I cant . And I agree that the roller 302 would be a better way to go, and if you could point me in the direction of the rebuilt shortblocks you were speaking of that are so cheap, I might consider going in that direction.

How much do you think I could get for the 260?

I do not mean to offend anyone but someting has to be said: This is my car which I dont plan on selling, therfore I will build it the way I want to. A car is a machine and shouldn't spark so much emotion. Sure, I like my car as much (or more than) the next guy likes his, but the fact still remains that it is a machine, my subordinate, and I will do with it as I please. My intentions are good but that dosen't mean they conform to "The Norm" of pampering the all important, rare 260 (which isnt !!THAT!! rare). I hope that nobody takes this the wrong way as it was not intended to be offensive, just my views on the car.

Tyler

 

[SoCalCruising]

Tyler, there is very good chance that you will swap cams, intake and carb, and wind up with a motor with less overall performance under 5K RPM than you now have. You will assuredly lose throttle response and low RPM performance. If you are going to build up the Crown Vic roller block later, I would just wait. I've been waiting since 2000 for my 331, which I am only now, finally, in the midst of final assembling.

I'm not trying to be parental (although I AM old enough to be your father), just coaching a bit. I once did what you're thinking of doing with a Chevy 327 - way back in my younger days. Turned out crappy because it was a compromise, someting like what you are proposing. Sorry.

The only reason that I would "accept" for what you're planning is that you want some engine-building experience before you try the 302-based motor. You'll get that all right, but you also run the risk of having your ride out of commission if something unforeseen happens. At least with the 302 motor, you can build it on the side and have your ride up and running while you do it.

BTW, my ride is an original '66 fastback GT, which I have completely "butchered" (as some might describe it) in order to make it "mine". I'm like you in that way - make it what you want it to be. Oh. I have no idea what your 260 might be worth. Try monitoring Ebay for something like it.

Geez, I might even be older that D.Hearne :-(

 

[tylerrocks]

Ahhhhh, Thats what I needed to hear, LESS horsepower es mal bien. I did not realize I could get less horsepower, and to tell you the truth I still cant quite comprehend it.

I know the speed demon 650 is a little much, but is it WAY to much? Didn't shelby put 750's on his cars?

Also, everything I've read says that the edelbrock RPM (not even an air-gap) is a good middle-of-the-road intake, now I realize that In this specific application I am asking for low end power, but I would ultimatly like to build up the 302. Possibly even a 331 like yourself. I think the EB RPM would fit it nicely. Is this the part that would decrease my low end? I bought the Carb&Manifold for $350 so its no sweat off my back. Heck, It wouldn't hurt anything to TRY right?

And surly the stock cam can be improved upon?

I know that I am dealing with some people on this forum who are much more experienced than I am, I just dont like people telling me that I have to keep the engine original. I respond much better when people tell me I could lose power. (dont tell me, tell me WHY)

BTW, while I dont like the stang out of commision, I do have an Econo-Nissan pickup that gets me around when it is (thanks mom&dad)

Tyler

 

[S-Car-Go]

Another post you probably don't want to read but I wanted to add my $0.02.

Even if you pick up an extra 100hp with a cam you will a) loose low end torque because you are moving your range of efficency to a higher RPM. Basicaly giving up low end to gain top end. b) You'll never feel it because of the 3 spd and 3.00's. No fast car was ever built with a 3 speed manual.

Put in the T5 and use the cam $$ to do a gear change to 3.55 or 3.80. This will give you more performance than a cam swap. Since you're low on funds, pick the right mods that will gain you the most performance, not the ones that sound sexy.

If you can swap the stock roller block in, that would prbably give you more power across the board than a 260 with a cam. and it will run better/longer on unleaded gas. It has hardened exhaust seats.

The Performer RPM IS a good midddle of the road intake for a 302. A 260 is not a 302... Same goes for the Demon carb. The shelbys had a lot of other mods and were built to live @ 6500 rpm's.

 

[SoCalCruising]

S-Car-Go did a good job explaining. The takeaway statement is that you won't be increasing torque, most likely, with the cam and intake swap you are contemplating, just moving the torque peak higher in the RPM band. Your hp peak is about 1000 RPM above the torque peak (just a rule of thumb, not absolute), so your power will also be higher - maybe up where you don't want it. Moving it up means you take it away from down low. To compensate, Shelby used 3.50 gears, 4-speed, headers, and a solid cam so that 6500-7000 RPM was doable. That was not your stated goal, so I point out the mismatch of expectations to what will be your reality.

Any cam that would help the 260 would be inappropriate for your 302 build-up, even more so for a 331; hence, a waste of money.

The key for you, IMHO, is delayed gratification. Wait for the 302/331.

 

[D.Hearne]

5.0 short blocks can be had for as little as $350 (exchanged) I went this route a couple years ago with my Ranger. Bought an "el-cheapo" short block, changed the rod bolts after discovering that they'd reused the stock ones and torqued em to 50 ft/lbs. This operation was done against everyone's warning that you can't do this, without resizing the rods. Also without taking the motor apart I also swapped the stock roller cam out for a B303 Ford roller. This short block already had Silvolite flat topped hypereutectic pistons ( 40 over) and was remanned by City Motor Supply in Dallas Tx. ( yea they've got a website too) Anyway, other than the rod bolts being reused and torqued too tight, everything else seemed to be top notch ( with the exception of the timing set) I bolted on a set of home ported E7TE heads and a Ford A321 intake, topped with a 650 Holley DP carb. I beat on this motor, daily for over a year, with a 4 speed toploader in my 89 (3800lb) Ranger. I then swapped the heads and intake to a set of Canfield aluminums and a Vic Jr. then beat on it some more, with freeway blasts up to 7500 rpms for 4 more months. Finally it cracked a cylinder wall. The rods and rest of the rotating assembly never gave up the ghost. Bottom line is you don't HAVE to spend the bank on a good shortblock, the stock 5.0's are plenty tough for most people, and with hydraulic roller cams, are a cinch to get power out of with the right heads and intake. Sell the 260 and build or buy a good 5.0. The 260 isn't what I'd call a common motor by a long shot and they sure as hell aren't building any more. Let some one take it and treat it like the ( hate to call it that) artifact that is truly is.