Over the last couple of weeks I was involved in helping tune a 4V 4.6 Ford with a set of very big Crower cams. The customer insisted on using the cams even though he was told and was aware that the car would likely not run well under normal driving conditions. Well, that would be an understatement. In spite of many hours of tuning, there was NO WAY to get the thing to run acceptably. There was simply no throttle response below 3,000 rpm. In fact, if you slapped the throttle open at <3,000rpm it would not only usually stumble big time, it would often actually stall.

Monday, we swapped in a set of smaller cams and had the thing tuned and running fine in about 20 minutes. The bill for this job was astronomical, and it was lowballed just to be nice. Word to the would be wise: don't pick the biggest cam that someone makes for your application. The smaller cams also made almost 40 more peak hp and it drives like a stocker.

Rich

 

Unfortunately, a lot of street car guys with medium knowledge overcam their car trying to get big horsepower and forget that their car would be a whole lot more fun with a lot of bottom end torque since the engine lives 99.8% of it's life under 3000 rpm.

 

Rich,

What size were the cams in comparison to one another?

Bret

 

How big was it????

 

I am also curious.

 

LOL, brought back memories of my close buddy with whom I tried to convince his cam choice was toally wrong for his application. He had a 496BBC built and was at 10.1:1 compression, ported 781 heads only flowed 299cfm @.700, 4.11 gear with 28" tire, and 3500 stall. The goofy guy ordered a cam with 286/295 @ .050 ACTUAL duration. This thing is a total dog the first 1/8mi and then it starts to come on after that. He's happy he can run pump gas but since he's losing soo much compression he could probably run 50/50 gas and water big motor light car and best has only been 10.999.

Some guys you just cant reach.

 

Hell, just throw a Roots blower on it! That'll Git R done!

 

"bad" cams = 228/244 @ 0.050" 114LSA
"good" cams = 222/224 on a 116

Rich

 

Many of you are going to say that is small but consider displacement tames duration to some degree and 4.6L is a whole lot less displacement than we play with.

I am glad to see someone post something like this to help people learn from the mistakes someone else already made, I know two locals that went 230+ on stock headed LT1s one sold the car and the other became a garage queen. They loved it for a few thousand miles then got tired of it. Sort of like open headers are cool for a few miles and that is enough.

 

I agree, we are talking about a motor that is about 70 cubic inches smaller than your average small block chevy (350) and more than 100 cubic inches smaller than a 383. I could easily see over camming it.

 

Don't forget it's a 4V. The same cam is going to act bigger with the larger valve area.

Rich

 

It's not the 228 that is a problem, but the 244 is a serious mismatch for the exhaust. No need to run a 16deg split on a 4.6 4V.

These are very capable motors, just lacking the cubes to make it a serious contender without some boost. I have one here that needs put to use.

 

The car in question made ~670rwhp with stock heads and bottom end and
<20psi. As to how long it holds together with a stock bottom end, that's another question altogether.

Rich

 

Most people don't understand that the cam is only part of the big picture.

Heads/valves, induction system, converter stall (if an automatic), rear end gears, vehicle weight, all play a part in what size cam to get. Getting a cam that starts to build power over 4000 rpm isn't for a street car. Others don't realize high lift or long duration cams are not a simple swap since it causes valve train problems or piston to valve problems.

I plugged a bunch of cam specs into DD2000 for my engine when I put a roller into it and found a cam I really like in an old Erson cam. I've seen new cams and inputed the specs and have yet to find one that gives similar results. Without actually doing a cam swap, I'll never know if a different grind will be better or worse. I don't care about bottom end power. I launch at 4500 rpm and my converter stalls, or at least did stall with my old engine, at 5700 rpm.

In a car that has to be driven on the street, it's a completely different story.

Look at Stock Eliminator cams. Max lift of stock OEM but every other spec is unlimited. Try finding a "stocker" that idles under 2000 rpm with such a low lift cam.

 

i dunno my car drives ok on the street with the 290 cam.. i havnt driven it that much on the street cuz its not insured yet but it drives ok and when u put that pedal down instant throttle response cam makes its stuff at 6200 where my shift point is

you guys think there is another cam for my app that might be alittle more streetable (not complainin on how it is now though)?? guy i bought the car from was making a drag car but i bought it to put on the street and be my daily warrior