Comp xe274

[mellow_utah]

Hello all, I have a 78 360 out of a van and I bought a comp xe274 cam. Wondering if installing that cam would be pointless without replacing the stock heads" i also have the recommended springs for the cam, lifters and double roller set. I'm thinking of pulling the motor to repair some leaks this winter and thought id do the cam too.

 

[fishy68]

That cam is right at the limit of how much lift you can get away with on stock heads. As far as replacing them I don't think that's needed. They just need the valve guide cut down so their won't be retainer to guide interference. If I'm not mistake that cam also calls for dual springs which won't work on those heads unless the spring seat is opened up big enough to accept them. IMO it's too much cam anyway for a 8 to 1 compression 360. If you have an automatic you also need to use a 2800-3000 stall converter or it'll be a absolute slug down low and probably won't want to idle in gear very good.

 

[70aarcuda]

Look for rotators on the exhaust valves instead of normal retainers....those need to go...

 

[OldmanRick]

As "fishy" said, your into the double springs with that cam. A XE268 or a 265/275DEH would be better as far as using single springs, but you have what you have.....

Depending on your gearing, the converter choice will determine how well the "274" runs, and it "can" be done. Just make sure it's tuned well, as it will like a lot of initial timing to be comfortable on the street with low# gears.

 

[mellow_utah]

Well thanks all, sounds like its better for me to wait on the cam swap. It's a stock 727, and has a stock 7 3/4" rear end still. In regards to compression, would it be better to use some domed pistons or use smaller chambered heads? I'm new to mopars so bear with me would it be better to find a magnum or build this?

 

[fishy68]

If you want a bigger cam go with one of the smaller ones Rick mentioned. That way it'll still have ok torque down low. What you have is fine to build on if it's in good condition. Most Mopar heads are about the same CC's so to raise the compression you need aftermarket pistons that are closer to the deck. 70's 360 pistons are usually way down in the hole. Mine was .090 in the hole. Thus the reason the compression is so low. You can install magnum heads that have slightly smaller closed chambers but you won't get over 9 to 1 even with a thin gasket and it's not a cheap conversion. If that 7-3/4 isn't a sure-grip (posi) it probably won't last long. They weren't very strong. If you find an 8-3/4 to upgrade that's fine but don't overlook the 8-1/4 cause it's a pretty strong rear too and a whole bunch cheaper.

 

[mellow_utah]

Thanks for the info, if the pistons are the way to go a strokes kit may be in my future it is a sure grip rear end but I have been reluctant to add too much power as I've been unsure of what it can handle. My background has been in big block fords and 9" rears lol

 

[OldmanRick]

At some point, you'll over power the small rear end, although the sure grip unit's are pretty stout. As Fishy said, a 8.25/8.75 will probably be something you should look to as a upgrade. Keep in mind that a good shape sure grip 7.25 can be sold to someone doing a Slant 6 or mild 318 build, for a reasonable amount of $$$.

As far as the engine, it's really dependent on what you want out of the car? Building a engine around a cam is not really the best way to plan one, but if you want to use the XE274 you have, the LA360 with KB pistons and a good valve job can make some pretty serious power for a street A body. Low 9's compression with pump gas and some good bolt-on's will make a streetable 300+ horsepower, and in a "regulation" weight A body car, it's easily capable of deep 13's in street form.

Now if that's not fast enough, the 4" arm may be the way to go for you? With the stock heads, I'd build it for torque.....like 450 lbs/ft over a wide rpm range. That alone can put you in a drivable 12 sec car.

 

[mellow_utah]

Honestly, this is my first small block. I'm used to built big blocks with the feel of the torque. I have a big block torino I'm thinking of making more of the family cruiser. Originally I was going to drag the torino. It's big and heavy so I think the scamp would be the better street/strip candidate. I havnt seen many 8.75" rears near me so I've been thinking of doing the 8.8 swap or maybe a 9" because I find both of them everywhere. Originally I was thinking of a 440 for the scamp but I got a deal on the 360, air gap intake, cam, double roller, lifters, springs, etc. I'm not really an engine builder, I'm sure I have enough know how to assemble the engine but definatly fall short on picking the right parts to assemble lol

 

[mellow_utah]

I don't need to use the cam, I just got a deal on it and wondered if I could make it work. I was going to buy an xe268 instead from the same guy but it had a flattened lobe.

 

[fishy68]

Honestly, this is my first small block. I'm used to built big blocks with the feel of the torque. I have a big block torino I'm thinking of making more of the family cruiser. Originally I was going to drag the torino. It's big and heavy so I think the scamp would be the better street/strip candidate. I havnt seen many 8.75" rears near me so I've been thinking of doing the 8.8 swap or maybe a 9" because I find both of them everywhere. Originally I was thinking of a 440 for the scamp but I got a deal on the 360, air gap intake, cam, double roller, lifters, springs, etc. I'm not really an engine builder, I'm sure I have enough know how to assemble the engine but definatly fall short on picking the right parts to assemble lol

My Pop's 65 Rambler has a Ford 8.8 someone installed in it and it needed brakes so I had to research it cause we weren't sure what it came out of. When I measured it I was surprised to find that it had identical measurements as the rear in my 68 Cuda. After a lot of research it appears it originally came out of a 95 Ranger. Naturally all the factory brackets had to be cut off and perches welded on but it's the exact right width and driveshaft offset and has the 5 on 4-1/2 bolt pattern. If you see them a lot that'd be one to look for. Measure it to make sure we are correct about the dimensions before you lay down money on it