I'm running the comp cam now and I want to know if the HOT cam would run better as fas as gas milage, torque, and idle quality. I will run my 1.5 aluminum rockers instead of the 1.6 recommended with the HOT cam, so lift wil be .492, I think. I don't want to change my valve springs which are comp 981's.

 

When you say LT4 hot cam, what year specs are you talking about? I have an LT4 cam in my 350 but it is from the 96 specs. It has 204/210 dur. @ .050 with .478/.480 lift and I believe 112* seperation.

 

By hot cam he is referrring to the LT4 hotcam produced by gm performance parts. I believe it is 218 228 .525 .525 lift. or something like that.

I have the xe268 and like it, but I dont know exactly how much better you would be in the areas you mention w/ the hotcam. I do know that the hotcam is a roller cam, and I dont think that they made one called the xe268 that was roller. If you converted to non roller do you still have all the roller stuff? One thing that I will mention is that the xe268 has a 110* seperation instead of 112*. The 112 will give you a little bit better idle along w/ the slightly lower duration.

So did you say you dont have much torque? I dont seem to be hurting for torque in w/ mine, but I have a 6 spd. I had it w/ an auto w/ a 3000 stall, which also was kinda fun.

Like I said though, there should be some difference, but this is the only aftermarket cam I have ever used as of yet, so I dont really know how much of a difference it would make going to the hotcam.

Ben

 

So you have a 90 block with a flat tappet cam? I assume so if its the xe268h. Do you still have the spider and other stuff for a roller cam? If not you could always buy aftermarket roller lifters.

I currently and using the XE269HR or XM270HR depending on whether you ask them for a car cam or a marine application. The specs are identical though. 218/224 at .050 and .495/.503 lift. 112 deg seperation. Those specs are very similiar to the hot cam.

I guess I'll state the obvious. The roller cam profile opens the valve quicker for the same amount of duration. So if you stay with similiar durations your valves will open quicker getting the higher lift flow out of your heads for a longer amount of time than the flat tappet. You would think that would give you a little more power.

 

I still have all of the roller stuff from my L98 days and it's just sitting in my garage tempting me to use it. The LT4 hot cam has less duration than the xe268 but more lift and it's a roller and I will only be using 1.5 ROCKERS with it. I am worried about losing over all horsepower and rpm. Any ideas what the red line would be with the hot cam? I want at least 5600 rpm.

 

Yes, 5600 RPM or so. It does have a better idle then the XE268 and probably would be better bottem end wise. GM grinds tend to be better then aftermarket as far as idle+ then aftermarket cams. The 268XE doesent have all the low end grunt one might expect, I used one on the last build and it was difficult breaking the tires loose but it pulled hard compared to the stock crate cam that it had before but I wasent impressed but then driving the BB 402 around for 8 months no small block impresses me anymore.

LT4!!!!!!!!!!!!!!

 

I can`t see the gain (if any) being worth the effort.One other thing I did notice is that you are running a 600 carb.A 750 might
give you a better bang for your buck.Have you run this car yet?

 

I had a 750 carb and it just used alot of gas. I switched to the 600 and the power was the same and the lowend improved. I've ran at the track with streets and stock suspension and all I got was alot of wheel hop. I ran a corrected 13.5 at 105mph.

 

GG is correct for carburation. A 750 doesent fly at 5000+ above sea level on a SB, unless its jetted way down..............way way down.

 

http://www.chevyhiperformance.com/techarticles/67838/

LT4 HOT cam 412 hp 423 torque

http://www.73-87.com/chp/gm3505.htm

XE268 402 hp 415 torque

Not the exact same engines but you can gather some information there.

As for not having enough torque I don't understand that. I have a Vortec 350 with the XE268 cam in my S10 Blazer and have plenty of low end grunt. So much that I RETARDED the cam 4 deg. Blazer weighs 3665 lbs with me in it 700R4 with stock V6 stall 4.10 gears and 28 inch tall tires. It's good enough to push my brick to a 12.6697 @ 107.94 mph quarters with 60 ft times in the 1.88-1.92 range on 275/60R15 Radial T/As leaving at 1100 RPM.

Edit: I'm able to get 21 mpg on the highway driving very EASY and average 18-19 mpg driving very EASY. I believe I could do better if I went down on jet size but I can't find my 71s so oh well.

As far as idle goes mine idles fine at 650 RPM. Only problem I have is when it's cold but that's cause I don't have a choke.

The only time I was unable to spin the tires at will with a 1/2 throttle push was when I had Hedman 1 1/2 shorty headers. As soon as I put on the Hooker Super Comp 1 5/8 headers I could peel out anytime. That was with 3.73 gears as well.

 

Were you running the hedman y-pipe previously and moved to Super comp y-pipe after, or did you even run a y-pipe

 

True dual 2 1/2 with a Dr. Gas X pipe both times.

 

I can't take it. Roller block, roller hardware, more lift, better idle, better gas mileage, I've gotta do it. Today I ordered my HOT cam and double roller chain for the 87 later OE roller cam. I think that the HOT cam will work better with the 2000 (basically stock) stall converter I have. Besides I never wind the motor to 6000 when I am on the street so I think that this cam will be more streetable. Something else is bothering me too. When I first put my motor together I just changed the valve springs without checking retainer to seal clearance. I thought I could get away with it but I was wrong. The retainers destroyed the seals and were hitting the valve guides. Then I pulled the heads and had them machined. I put them back on and it runs fine, but I still wonder if the lobes on my XE268 are damaged. Oh well. I need Lower Ctrl Arms!!!

 

Good luck. Keep us updated!