**I've posted before on this, but I'd like to be more organized and complete in my thoughts this time around.

I'm looking for advice on what cam to swap into my fresh 350 (bored to 360) to squeeze a bit more out of it. I'm willing to do a retro-roller swap, but if the money can be well spent elsewhere, I'd rather go for that instead. Changing the heads is not an option, they hold sentimental value.

BLOCK: 1983 350 4-bolt Non-roller

CURRENT CAM: 1105 ELGIN; @ .050" -> Intake lift: .420, exhaust lift: .443,
intake duration 204, exhaust 214

HEADS: 1.6/2.02 valve 1971 Corvette 77cc, fully ported, double springs, 487 casting

PISTONS: H617CP SpeedPro Hypereut.; domed with valve reliefs

INTAKE: Edelbrock RPM Air Gap

CARB: Holley 650 DP

EXHAUST: True-dual straight pipes, Flowmaster 40 series 2 chamber, Hedman Longtubes

The current cam makes peak HP right around 5600 rpm in this engine. I've got 4.10's out back, so whatever cam would compliment a T56 with 4.10's well is what I'm shooting for. The current piston/head combo is good for between 10:1-10.5:1 compression.

Pics of what we're working with:



This is a street engine that sees the track quite a bit during the season. Goes 8.8x @ between 80-82mph on street tires currently. Driveability is not a huge concern. Any suggestions?

 

You could benefit from a little more duration and lift. try looking into comps xtreme energy series they are good cams and might be what your looking for.

 

I've been interested in the comp cam xtreme energy cams. Anyone have an idea on which one I could use to get the most out of this setup?

 

XE274 would be nice.

I wouldn't bother with a retro roller set-up.

 

I'm going to save money for the roller 406 I'm putting together. I'll just do a simple flat tappet swap in this engine for now. Any idea how much more I might get out of the engine with the XE274? Should I be worried about piston to valve clearance? I'm thinking I probably won't gain much more than 15 or 20 crank hp out of the swap, is this a conservative estimate or can I expect a little more?

 

An XE268 is my suggestion, and I'd expect at least 30 horses over that Elgin cam.

 

Sounds like a toss up between the XE268 and the XE274. What's the reasoning behind the picks?

 

the 274 is a better match for your domed pistons, and will give more mph with your horrible axle gearing, but the smaller 268 is a better match for the flow of the heads and your horrible first gear ratio. Do the wise thing and switch transmissions, then the 268 will better match the overdrive you'll get with a wiser trans.

 

You're losing me on the T56 bashing thing... I'm not sure I follow the logic. I'm eager to learn, but could you explain what you mean a little bit? Switching the transmissions really isn't an option - I'm in love with the one I've got!

 

I'm bashing the TH350. Aren't you using a TH350? If you're using the T56, then there's no way you're gonna get the 274 cam to cruise in 6th gear. And I always bash the TH350.

 

Nope, I've got the T56 in there. I don't hardly use 6th as it is unless I'm moving pretty good on the highway, above 60-65mph. Other than that issue, will the 274 work for my application? I'm mostly concerned with piston/valve clearance. I don't have experience in measuring this. I built the engine that's in it with my uncle and will be getting his help with the cam swap, but I just wanted to present a cam to him for consideration. If we can agree on the 274, I think I'll try and go with that.

 

Another quick question: Will I need to change valve springs/pushrods from what I currently have? I don't know the specifications for the springs...

 

I just see so many threads that sometimes I get the wrong trans with the wrong person, or other little goofs. Sorry, I meant no offense to you personally. I always mean offense to TH350s, but not someone who's stuck with one because the person is too poor to spend $75 for a used 700R-4.
Anyway, If you're prepared to give up use of sixth gear entirely, or swap in the rare 4.30:1 gears, then go right ahead with the 274. It has .487/.490 lift, and your pistons have valve reliefs for 2.02 / 1.60" valves, so odds are 99% in favor of having no issues of any kind.
Nearly any springs will work, but for the first half hour of running the new cam, the softer the better, and 1.5:1 rockers only. If you want to change rockers or springs or both after that first half hour, fine. for the rpm range of this 274 cam, try to use springs with 90-110 pounds on the seat. The less open pressure, the better.

 

Would buying the complete cam swap kit that is offered be the best idea, or can I get a better deal by shopping around? Would the use of 1.6 roller tip rockers be advisable or should I stick with my stamped steel 1.5 rockers?

My biggest concern is the piston-valve clearance. But I agree - it appears it will not be an issue.

 

I use a Comp XE cam in every engine I build, have great luck with them! I just built a 350 TPI for my 86' Iroc will have it started this weekend has a XE262H, will let you know how that goes. The last motor I built was a carbed 350 that went in an 87' Mustang notchback, went 10.97@120 with a 1.53 60ft. on pump gas and drag radials. I used a Comp XS290S cam in it.

 

I'm pretty sold on the XE274 cam setup. I'm getting the car repaired and painted first, though... Some woman scraped up the from drivers side pretty good. Who hits a bright red car other than a woman?! Should have this swap done in about a month. Will post back with results.

 

I'm glad to learn that I'm not the only one here who puts SBCs in fox mustangs. Got a link to a build thread? I do, we might could learn some ideas from each other?

 

I don't have a build thread for it but I do have some pictures I could post, don't know what the forum would think of that though? I can tell you every part on the car. I don't think I want to jack this thread to do it though, any ideas?

 

Here's a link to mine, and you can post in my build thread, all you have to do is register, same as you did here.
http://mustangforums.com/forum/4-cyl...y-intro-6.html

Now back to Plasmeh's build.