Thanks, I will keep calling comp,

 

Ok so I will put in my .02.
248 intake and 254 exhaust. Is this measured at .050 lift?
If so that's pretty good size cam for a 355 CI engine.
If it was my engine I would install a new cam with about 15-20 degrees less on both the intake and exhaust. With the 110 it will still have a bit of a chop.

 

Yes at .50 this is the cam in the motor now, definitely more strip than street for me.
Thanks for the input. One I'm looking at is about 24 degrees less on int,/ex
comp extreme energy hydraulic roller 224/230 - 110
1900-5600

 

Look up a few David Vizard cam videos on you tube. Especially the 128 cam rule. Good luck. And then the carb sizing for your engine. The cam you mentioned in post #1 is getting a lot closer. Good luck.

 

It's all about the cam/gear combo.
That 248/254* duration is at .050" right?
Your cam is extreme on the high rpm side, and your gears are very low on the rpm side. They do not play well together at all.
Your choice is to go all-in on extreme, or all-in on mild, or meet in the middle.
That big cam needs basically 411s or 370s, minimum. And it will still be nasty, and want to rev to 7K.
If you are going to short-shift it at 5500, you are only using half of it's power range.

I for one like your new 224/230* dur cam choice.
It's a good streetable performance cam, with a lope.
Especially if you are never going to rev it past 5500. It will pull hard a little past that.
It will hit hard at 1900rpm within the range of your 2200 convertor.
It goes well with a 650 DP carb.
But it still will not like the 2.87 gears nearly as much as the very mild stock cam did.
As long as you also change the gears, to 336-355-370, then it will run fantastic!
And that combo will probably kick the big cams butt below 60 mph!

 

Thanks for the input
as soon as I get the cam in and running right, after 500 miles I'm putting a new Differential and stub axel. I have been looking at 2, not sure which just yet 3.31 or 3.54, maybe more or less, I will cross that bridge after 500 miles and more research
thanks again

 

Reading through your posts, it seems like you could have some other issues going on other than just a camshaft issue.
Do some research and make sure your timing and distributor are set up correctly for your engine.
Also look for any major vacuum leaks, especially between the intake and block.

Before you decide on any particular cam, make the decision on what gears you plan to run otherwise you may end up changing the cam again.
Why, because it’s like everyone has been trying to explain to you (but failing to make their point) is that the cam and gearing need to work together.

Also decide on what you are using the car for, your driving style and also how you plan to use the car.
You’ll want different gears if you want to cruise on the highway and different gears if you want an in town hot rod going from light to light.
Different cams as well.

Look at more than lift and duration on the specs.
Your cam choice should also work with your engine’s compression ratio, heads, intake and all the components, including the torque converter.

Building a performance engine is a science and I’ve seen shops who build beautiful cars, but know nothing about building the engines they install in them.
And sometimes the advice they give isn’t always the best.

Be patient and talk with Comp Cams tech support before you make your choice
Have a plan and make a decision on your rear end gearing before you call them otherwise they might tell you to call back after you decide.

Another important item to consider, is you need to know what valve springs and lifters that are currently installed in your engine.
Many engine manufacturers will install higher spring pressures than what is necessary, which work good in a racing engine but don’t work well in a street engine and the higher spring pressures can shorten the life of your valve train components.
What ever cam you choose, match it with the valve springs, rockers and lifters that Comp Cams suggest.
And always check your pushrod lengths any time you change any component in the valve train.

 

I have that exact same Comp cam in my Corvette. I think you will like it a lot better than the "bottom of the page" cam you have currently installed.

 

thanks Crimson Thunder, I was hoping someone might have that cam installed. Do you like the sound and performance? I know you're setup is probably not the same as mine but I was just curious.

 

I have similair wants with my car as it also never sees 5500rpm and just sees spirited street driving. I used the smaller comp xe270hr for my 10.2:1compression engine as the dyno software showed the best overall torque and hp IN the correct rpm range that I want that power to be there. I have 3.55 rear gears I swapped in to replace the 3.08 gears It had up until this summer. honestly that gear change made a minimal effect on my combo. your gears are a bit weaker so you would see more change. the downside though is without an ovrdrive in that trans you will also be turning much higher rpms while cruising. this is why im installing a 2004r trans. the following desktop dyno numbers are optimistically higher than I believe they really are (its likely only around 375hp) and the timing @ adv number should be set to 0 vs 4 which lowered the results here in this simulation but this just givs you a ballpark idea of the rpms at which the power curve comes in with this much smaller 218/225 cam.
Im building a 406 now and ill be using a larger summit 1223 retro roller cam for that sinc the larger displacement allows it with less tradeoffs.

 

Also keep in mind, it is the overall grind of the cam that makes it build torque and horsepower at a particular rpm in the engine.
we spent hours going over different cam grinds for my engine, but once on the dyno, we found the cam was not building torque where we specifically wanted it, so we pulled the cam and went with a cam that actually had higher lift, but the other aspects of the cam caused the engine to make more torque at lower rpm, flattened the torque curve and made the engine build more power where we wanted it.

 

Thanks augiedoggy, i had my car on the interstate a little while breaking it in. The 2.87 gears let me run 70 at about 2600rpm's. I am changing the gears after the cam for more spirited driving around town but I want to keep a happy median between the interstate and town. I was thing about the 3.08 or maybe 3.31. I also have 17" wheels and tires which help, my tires are 27 1/8" tall
what software is that you are using?

 

I built an excel spreadsheet for you . Attached.
Your current cam has a 3200-6200 rpm powerband. (A)
Your new projected cam has a 1900-5600 rpm powerband. (B)
Your original stock cam was more like 800-4800 (C)

Lets call them AB&C and see at what mph you hit that powerband in 1st gear with your current rear gear
2.78 gear:
(A) 37 mph
(B) 22 mph
(C) 10 mph

See the problem now? One cam hits hard at 10 mph and the other waits until 37 mph.
Your current cam could hit 80 mph, in first gear!

So on the sheet, you can look at those powerbands, and their mph speeds, with the different gear ratios.
The 3.36 & 3.55 & 3.70 look much better, up to 60 mph.

But as you change gears, from 2.78 on up to 3.70, your 70 mph cruising rpm goes up, a lot.
2400, 2650, 2900, 3100, and 3200.

It becomes harder and harder to have good stoplight rpm, and interstate cruising, without an overdrive trans.

Every modification is always a compromise, somewhere!

And only you can decide where that compromise should fall.

Good luck.

 

Thanks leigh1322

 

Think of it this way.
The cam change will make the biggest difference.
Instead of hitting the powerband at 37mph, it'll happen 15 mph sooner at 22 mph.
The gear change will help that some, but not as much..
Instead of hitting the powerband at 22 mph, it'll happen 4 mph sooner, at 18 mph, with the 3.36 gears.
At least that one is a tolerable highway gear. 2900 @ 70.

 

A lot of talk about 70MPH RPM. I've had my 77 for a fair few years.
I've flown across the great plains in America at some extremely high speeds, RPM's be damned! All day long accross South Dakota, Wyoming, Montana. Seriously no issues.
I've run hard from Brisbane to Cairns in Australia. About a thousand miles each way. Running 70 -75 MPH and RPM's well above 3K. My car LOVES it! It's singing in it's sweet spot right around 85 MPH.
Why the bloody hell is everyone so afraid of a few RPM's?
These cars where designed this way!
I say, let em Snap!

 

Thank you leigh1322, I edited everything to my TH350. This is very helpful,
thanks again

 

I finally got ahold of the company that built my crate motor, the cam that was supposed to be installed was a

Howard 180255-10
2200-5800
231/235 @ .50
510/530 lift
110 lobe separation

The other cam I'm looking at
Comp Extreme Energy
1900-5600
224/230 @ .50
502/510 lift
110 lobe separation

When speaking with them i was told they didn't have the Howard in stock so they substituted which was their mistake. Someone less experienced pull the wrong substitution and I wound up the the monster cam I now have.
I asked if any other substitution changes were made like springs, push rod or rockers and was told no. I will however be reimbursed for the price of the Howard cam and something for labor but I doubt that will be much.

I don't see a whole lot of difference in these 2 cams but I am not that experienced.
I have a 2200-2800 stall converter in now that was hoping to tame the big cam. If I leave this converter in and use the Comp Cam, will my stall converter affect the performance or are the numbers close enough.
Will I get a good lope at idle with either cam?

 

This was a big help. After punching in new numbers for my TH350 I came up with
3.55 gears 3084rpm @ 70mph
3.36 gears 2919rpm @ 70mph

Not a big difference, both are tolerable but still undecided. Would there be much difference in bottom end take off ?

 

You won’t see much difference between the 3.36 and the 3.55, if you feel anything it will be the change you’ll feel by swapping from the 2.87’s.
Your cam choose 1900-5600 would probably work better with the 3.55 but if you go with the 3.36 you might look at cams that come on at 1500.
I know a lot of people worry about wanting a cam that creates choppy idle.
You should worry less about a choppy idle and more about how the cam performs and where it produces power.

My 496 has very little or no chop at idle, but everyone instantly knows it is a monster as soon as I push the go peddle, even a little.