Comp Cam Extreme Energy

[LinceCuda]

So Bobby called me today and gave me good news on my 1974 360 J-heads. He told me they tested out great no cracks and that they had already been upgraded to the larger valves (2.02) and they were in great shape, and would work well on my 71 340 block. So I went up there and he went over cam selection and we decided on Comp Cam XE274H Extreme Energy 2200-6000 rpm. He felt with Dr. Diff 3.55 rear gear kit w/sure grip, 4-speed, Carter 800cfm carb, 10.3 Speed Pro forged pistons, 457 factory forged crank, and Eagle forged rods this cam would work really well. I also dropped off my complete rotating system to have it all balanced as well. I then read some on line forum comments on my cam selection and listened to some youTube videos and I was pretty dang impressed. Roberts and Sons shop has always served me well and others so I guess that's why they've been around since 1929. Cam lift in. 487 ex.490 duration in. 274 ex. 286 and in. 230 ex. 236 @ 050 and lobe separation is 110.

[Shane Kelley]

I run the 284H in a 71 340 with 11.1 compression and it sounds and runs pretty good.  3.55 gears but mine is a automatic. The 800 cfm carb would work fine but in my opinion it's a little on the big side for street use. The throttle response is will be crisper with a smaller cfm.  Drag race is a different animal all together and then I would still run a 750. I really think 750 cfm would be the better choice. 

[LinceCuda]

I run the 284H in a 71 340 with 11.1 compression and it sounds and runs pretty good.  3.55 gears but mine is a automatic. The 800 cfm carb would work fine but in my opinion it's a little on the big side for street use. The throttle response is will be crisper with a smaller cfm.  Drag race is a different animal all together and then I would still run a 750. I really think 750 cfm would be the better choice. 

Thanks for your input Shane and the good thing about carbs is they change out easy. I have on hand the stock Carter Thermoquad which I thought was a 800, Holley 650 & 750 and a Edelbrock 600 to swap until It runs like it should. Thanks again 

[Rdchallenger]

I have the 262H for my 69 block 340 with no other upgrades besides the Airgap intake and a 750 Edelbrock carb. I was only looking for a slight increase from factory and the advertised rpm range will be perfect for me with either 3.23 or 3.55 gears with a 904tranz. Granted i haven't a clue if it's the right choice until i run it 

[LinceCuda]

I have the 262H for my 69 block 340 with no other upgrades besides the Airgap intake and a 750 Edelbrock carb. I was only looking for a slight increase from factory and the advertised rpm range will be perfect for me with either 3.23 or 3.55 gears with a 904tranz. Granted i haven't a clue if it's the right choice until i run it 

That cam you picked should be perfect for what you have, here's the chart I took a pic up down at the shop. I have the 2 with check marks I was considering and went with the 274H

[Chryco Psycho]

just for comparison https://www.summitracing.com/int/parts/lun-10200703lk

226 / 234 @ .050
.494/.513 lift
wider Rpm Band more lift
better choice IMO   

[cam440]

I run one in my 400 in my gto makes strong midrange power but falls over around 5500 rpm and they can be alittle noisey mind sounds like a solid cam lol , a lot of people say they are noisey google it , that's a nice cam neil but yeah I'm happy with mine still

[73_Cuda_4_Me]

I am running the XE274H in my '70 340 engine... with my 727 and stock torque converter (not original), and 3.23 rear-end, it wasn't happy at all from a stand-still... torque converter would stall at 1800, below where the cam power band was happy...

I put in a 2400 stall converter, and advanced cam 3 degrees to lower power band a tad, and LOVE how it sounds and runs now!

You will be running around 18-20 degrees advance at idle (750 rpm), and it will have a nice lope, and with your setup, should really rip!

Are you running stock dizzy??? I had some real fun with stock dizzy fighting mechanical advance at idle... finally got things sorted out by adding a limiter plate that tightened stock spring advance, yet kept advance all-in at 34 degrees... disconnected vacuum advance can.

[cam440]

yes its best with a 2400 plus stall for sure , mines a 2500 stall with 3.42 rear and its just frys the tyres is a nice sounding and performing street cam from 2200 to 5500 with a 4 speed will be fun

[LinceCuda]

Thanks everyone good to here from folks that are running this cam. Even with some negative issues seems like with a little work they were overcome. Hey 73 I do have a stock dizzy but I'm sure it needs to be rebuilt, so I haven't made up my mind what I'm going to do. I've looked at several pointless ones that look stock and was leaning that direction. Hey Psycho yep love the Lunati  have run them in in my drag car with great outcome, just felt this was going to be the right choice for my build now thanks for your input as always.