Comp Cams XE274H cam in a 493 RB Stroker Engine

[shoelesskk]

I recently removed the Comp Cams .507/.510 XE284H cam from my stroker 493 engine. It was giving me fits to try and tune. The vacuum was too low to operate the power brakes correctly and it lopey idle was too much for me. It also caused the engine to have an extremely rich idle possible because of the low vacuum. I installed the Comp Cams XE274H .488/.491 cam in the engine and man am I happy with it. I know most of the recommendations for the 493 stroker engines say the XE274H cam is way too small for this combination. But its vacuum is around 15 and it idles great at 800 rpm. It idles like you know its not stock but allows the car to maintain a good idle without searching for it. It is a torque monster and I couldn't tell the difference in power from the old cam. Off idle it will roast the tires and pull real hard way into the mid range RPMs. I haven't ran it too much above 5000 RPM yet, but I am pleased how it operates in the engine now. I'm sure the .507/.510 cam would work great once it was tuned but this car will be a car show car and not on the track. I like how the big duration cams sound in the 440 stokers but for me it was a nightmare and I wanted a engine that had good manners and put in drive and not have to worry if it would die at the next stop light. Here is my combination in case anyone has a similar build and wants a good cam with great street manners.

1966 Plymouth Satellite
440 bored .030 over
4.150 forged crank
6.760 forged rods
Keith Black -24 dished pistons.
Compression ratio 9.5 to 1
Stock 906 heads
Adjustable 1.5 steel rockers
Comp Cam XE274H Cam
Edelbrock Performer RPM intake
Holley Street Avenger 770 cfm carb.
727 Transmission
2400 stall 11" converter
8 3/4 with 3.23 sure grip unit

 

[lewtot184]

a few weeks back I rode in a dart with a 440 6bbl 5spd. the cam was a comp xs274. I was totally impressed at how well mannered the cam was and still had some cruise-in idle.

 

[69 GTX]

The 284 cam probably would have worked better if it was on a 112-114 LSA

 

[wyrmrider]

and with 3.90 gears and a looser converter and...better heads...and
274 sounds about right for that stroker
stock size 440 go shorter with 3:23 gears

 

[PurpleBeeper]

You know, I had a similar issue with my non-stroked 440. I was running and old 292/509 purple shaft cam & had HORRIBLE vacuum, like 4" at idle. I know some of that was my carb setup (which I've fixed 95%).... but I also put in a XE274 and had similar results as you.

 

[5.7 hemi]

My XE285 is runs GREAT in my 470!

 

[not so famous bob]

My XE285 is runs GREAT in my 470!

my extreme 292-s solid roller runs great in my 505. Manual disc tho! LOL

 

[5.7 hemi]

Manual brakes and 4 speed here.

 

[6PKRTSE]

I run the Comp XE292H in my little +.030 440 in my Charger with a Six Pack, A/C, power disc brakes & drive it all over on the street. I do run a vacuum canister hidden under the factory battery tray though but never had any tuning or braking issues.

 

[wyrmrider]

5.7 what's your rear gear any other details, just saying it runs great does not help much unless you say what you did to make it run great compared to the other post were ie did not
cheers

 

[5.7 hemi]

470, TTI headers, Stealth heads, 4 speed, Dana 60 with 3:73’s suregrip, 28 inch tall tires, Holley Terminator efi. Runs like a scalded cat on a hot tin roof! Now I just gotta get the Assassin traction bars dialed in so I can plant the tires and scoot.

 

[wyrmrider]

What I thought
great combo- FI covers a lot of sins
that 284 cam should work well with a stick and 3.73-390 gears
Auto trans guys have it tougher
I was checking and a Hellcat only turns 1600 rpm at 60 mph
some of the final drive ratios with the 8+ speed autos are down around low 2:1 2.20 for example
but not so tall tires

 

[383man]

If it works ok in your combo and you like it then I would run it as you are. I am sure you could have tuned the other cam to work good but if you did not want to fool with all of that and as you said its not a race car. Glad you are happy with what you have in it now. I run much more cam in my 493 and love it (264 & 270 @ .050 with .585 & .592 lift and a 110 LSA solid flat tappet) but I also run much more converter and gear with better heads and I run a lot of timing at idle with a very fast mechanical advance and I love how it idles. But that's the kind of gearhead I am. We have to run a combo that pleases us as to what we like. I would figure your 493 with that smaller cam would have very good low end kick even with your 3.23 gear. Ron

 

[shoelesskk]

Thanks for all the reply's and support. I believe most of my problems had to do with the 2400 stall converter and auto transmission. I could get the XE284 cam to idle great and sound good but once it was in drive it would bog down and stall out. Then I would have to adjust the idle up to 1100 RPM to get it to stay running in drive. If I had to do it over I would put in a 2800 to 3000 stall converter in, but I just wanted something a little more tame since I have A/C and power brakes. Also probably would have called a custom cam grinder and had one made specifically for my application. Maybe one day I can change over to aluminum heads and some 3.90 gears and try one of the solid cams. But for now the engine seems to run great for what I'm using it for. I think that's the most important part of any build is what will the car be used for. I have learned a lot of lessons on this build and just wanted to share.

 

[wyrmrider]

Thanks for sharing
everyone

 

[moparnico]

I recently removed the Comp Cams .507/.510 XE284H cam from my stroker 493 engine. It was giving me fits to try and tune. The vacuum was too low to operate the power brakes correctly and it lopey idle was too much for me. It also caused the engine to have an extremely rich idle possible because of the low vacuum. I installed the Comp Cams XE274H .488/.491 cam in the engine and man am I happy with it. I know most of the recommendations for the 493 stroker engines say the XE274H cam is way too small for this combination. But its vacuum is around 15 and it idles great at 800 rpm. It idles like you know its not stock but allows the car to maintain a good idle without searching for it. It is a torque monster and I couldn't tell the difference in power from the old cam. Off idle it will roast the tires and pull real hard way into the mid range RPMs. I haven't ran it too much above 5000 RPM yet, but I am pleased how it operates in the engine now. I'm sure the .507/.510 cam would work great once it was tuned but this car will be a car show car and not on the track. I like how the big duration cams sound in the 440 stokers but for me it was a nightmare and I wanted a engine that had good manners and put in drive and not have to worry if it would die at the next stop light. Here is my combination in case anyone has a similar build and wants a good cam with great street manners.

1966 Plymouth Satellite
440 bored .030 over
4.150 forged crank
6.760 forged rods
Keith Black -24 dished pistons.
Compression ratio 9.5 to 1
Stock 906 heads
Adjustable 1.5 steel rockers
Comp Cam XE274H Cam
Edelbrock Performer RPM intake
Holley Street Avenger 770 cfm carb.
727 Transmission
2400 stall 11" converter
8 3/4 with 3.23 sure grip unit

Did you have video from idling ?

 

[Challenger340]

Thanks for all the reply's and support. I believe most of my problems had to do with the 2400 stall converter and auto transmission. I could get the XE284 cam to idle great and sound good but once it was in drive it would bog down and stall out. Then I would have to adjust the idle up to 1100 RPM to get it to stay running in drive. If I had to do it over I would put in a 2800 to 3000 stall converter in, but I just wanted something a little more tame since I have A/C and power brakes. Also probably would have called a custom cam grinder and had one made specifically for my application. Maybe one day I can change over to aluminum heads and some 3.90 gears and try one of the solid cams. But for now the engine seems to run great for what I'm using it for. I think that's the most important part of any build is what will the car be used for. I have learned a lot of lessons on this build and just wanted to share.

I am very curious about your experience with the XE284 ?
To Wit:
"I could get the XE284 cam to idle great and sound good but once it was in drive it would bog down and stall out."

Do you remember where the 284 was Degree'd in at when installed ? or just "line up the dots" ?
Did you make any other changes/repairs when switching to the XE274 ? Carb, Possible Vacuum leak ? etc ?

I mean I'm glad it's now fixed and running well for you with the 274..... I'm just not all that convinced that ALL of your running/idling problems were the 284 Cam in the 4.15" Stroked 493 ?
And BTW....
We use BOTH the 274 and 284 all the time.... and we Engine DYNO them regularly using far better heads than your 906's, you need to be aware that the 274 is "all done" by 5,000 rpm.... NO point revv'ing any higher in your 493 because you are well into the downside of the power curve by 5,000 rpm with the XE274.
FORGET the "published" rpm range for the Cam.... it doesn't go there !