A while back I had posted a question to everyone who had changed their camshaft on their Vette's as to whether they did it again which cam would they choose. Well for the most part, most said they should have gone a little higher on the lift or at least I convinced myself that most said that.(LOL) I went ahead and took a chance and ordered the XR276hr Retro-roller Camshaft from Comp Cams. The reason I said I took a chance was because the first camshaft I originally had installed was a XE268 Comp flat tappet camshaft, but as luck would have it the mechanic accidentally rounded a cam lobe. My original set up was geared to work with the XE268, since I ordered some 64cc heads(E-Street Cylinder Heads), timing gear and timing chain. Well the E-street heads state on the installation manual that they are not compatible with roller cams. Well after talking to Edelbrock and Comp Cams and taking the advice given by a lot of people here on the forum, I took the chance and had the Retro Roller cam installed. Friends, I feel like it was the best decision I made. Granted it has only been 2 days and a 100 miles later. I just changed the oil for a second time, to make sure there are no shaving of any sort in the oil. Even though they say you don't have to break these cams in, I didn't want to take a chance. Too much $$$ invested. The cam sounds a little lopey and it worked perfect with my Quadrajet. Intake was also changed to a 2101 Performer intake. Guys if you want your L48/L82 to be able to keep up with todays 6 cylinders(LOL) this cam is definitely the way to go. I want to say conservatively, I believe I have beefed up my 190Hp L48 to well over 300HP and she sounds awesome! Right now what is under the hood is a 1980 L 48 350 with a XR276 Comp Retro-Roller cam, E- Street 64cc Cylinder Heads, Flowtech Long Tube Headers feeding into 2.5 inch straight pipes then about 3 feet lower behind the tranny, there is a 2.5 inch H-pipe, which then they dump into Flowmaster Delta 40 series mufflers. The car is pretty loud when the windows are down and very tolerable when the windows are up. It use to resonate pretty bad before with the other camshaft, but then I put the H-Pipe which helped lower the tone somewhat. Like I said today is only the second day of driving the car and she seems fine for now. I will post again on this post in a month to see if my mindset changes on this cam.

 

You are probably at about 380hp.......
Good job.

Jebby

 

I think your about right Jebby on the Hp although I have not dyno tested it. As you know, I took your advice on getting the 64 CC cylinder heads and getting a thinner gasket to increase the compression on the engine. It seems to be working pretty well.
Thanks

 

I know many of you all are probably thinking why the heck didn't you just LS swap the engine. Since, I would have probably spent about the same $$. My reasoning is that the previous owners of this car took real good care of her and I didn't want to make any very serious changes to her integrity and still have fun cruising in her. She had 40,260 original miles on her, but she ran like a dog. I figured I wanted to keep her with all the matching numbers and have a car that would be fun to drive. I know many might not agree, but in all fairness she was just going to be a cruiser anyway. She sounds good and she has some pretty good pick up now, so I think I have succeeded .
Yes, before I am asked I have all the original equipment boxed up and put away in the shed in case I ever decide to sell her.

 

Subscribed. I have the same Edelbrock aluminum heads, so I'm very interested in how this all turns out.

 

Never apologize for using a small block or a big block instead of an ls motor.

 

what did you use for lifters?

 

I ordered the CL 12-423-8 kit, those came with the roller lifters for that cam.

 

I'm running that exact same cam with AFR 195 heads. I bought the entire K kits with the springs, pushrods, and timing chain. I love it.

 

So far car seems to be running fine, although it started to make a little noise on the driver side cylinder head. I believe it is a rocker arm that became lose. I tried taking it out for a spin this past Monday, but this hot Texas weather sucks. I need to repair my a/c next.

 

Okay I am now 1 month into this new camshaft (XR276). The car runs pretty good and has good pick up using stock quadrajet. It seems to idle best at about 950 rpms. The only real drawback I can see is that now my car is picky on it's gas intake. She only likes 89 octane or higher. Car runs pretty good from first to second gear but comes to life on 3rd, because her pick up is real quick(3.08 rear gear). On a scale from 1-10 in comparing to original set up, I would give this new set up a high 8. I am wondering if it can probably perform better if I switched Carb over to new 750 Edelbrock or if I went with EFI?

Pros:
Nice sounding car: slight noticeable chop.
Car picks up faster than it use to.
Don't have to worry about adding zinc additive to oil since it is a Roller Camshaft.
Stock Quadrajet seems to work fine, but does need to be tuned properly.
Brakes and lights work well with vacuum pressure. I believe last tested yielded about 14 to 15 lbs

Cons:
Car only likes 89 Octane or better now.
Car sound inside was a little loud at first, but with some minor modifications it is now very comfortable. Customized a carpeted speaker setup that takes up 10" of rear compartment so it covers the old speaker enclosures and still has room for T tops. Also added an H-pipe to straight exhaust, so it dropped tone a little.
I am guestimating on mileage, but I think I get about 15 mpgs in the city if I am lucky.
Had to replace rocker arms with roller rockers; consequently, I had to replace the valve covers as well because new set up made them much higher.( high rise covers)

 

Have lars re do your carb or get a Holley. Get lars ignition papers. I steeper gear would help low speed.

 

I would expect with greater cylinder pressure and a 3.08 diff it would have a higher octane requirement. Switching carbs will not change that. The Q-jet is an excellent carb. Just need to get it set up properly. EFI will give you on the fly mixture adjustments, not more power, and does cost considerably to switch.
Sending the carb to Lars would be cheaper.

Higher stall torque converter and a shift kit is a very good mod as well for acceleration.

 

I have the Xe270HR myself and jumped from the flat tappet voodoo 262/268 cam. I also felt it was a worthwhile upgrade and it made quite a difference in how the engine runs. In my case I also have 64cc heads but they are iron and that along with the flat top 4.030 pistons and .015 shim gaskets gave me a higher 10.16:1 static compression which the 270hr cam helped bleed off a bit so my DCR was in the sweet spot for pump gas. I run 91 octane with no pinging.
This software is optimistic I know but I used it to compare the different option with my combo and it gave me the best numbers vs everything else I looked at that would still work with my 3.08 gears and 2000rpm stall... both of which will be changed soon anyway.