Too big a cam?

[Aussiemadonmopars]

So I'm starting to put a motor together, a 400" out to 500" using the 4.125 crank and 4.382" piston 440 source kit. I'm using the standard stealth heads, unported, and will at the very least change the locks for the valves. I have 2 cam choices, a 484" lift Grandma cam or the big comp cam - XE295HL-10. Would the bigger cam be too big for a street motor? I'm guessing it won't but I want to be sure. I'm kinda hoping the extra cubic inches will chew some of that big cam up and make it a bit milder. How should I expect to behave also with the heads unported? Too restrictive for it do you think?

[c00nhunterjoe]

The heads will be the biggest drawback unported on a big inch motor. I ran the xe295 in a street driven 440 with no issues with a 10" converter that flashed at 3500.

[Aussiemadonmopars]

Just reading up on the 440 source website as well, they are saying I could expect the CR to be up at around 10.8 to 11 :1. Would I be able to use 98 octane fuel?

[Aussiemadonmopars]

And the converter I have is a 3000 rpm TCI I think.

[c00nhunterjoe]

If you plan on upgrading the heads, stick the 295 in it. Will run fine at 36 degrees timing on 93 octane, unless you live in colorado mtns.

[Aussiemadonmopars]

Yep, later on definitely upgrade the heads but just curious how its going to run now. Also, there seems to be more options if you only bore the block to 4.375", kinda wished I went that way.

[c00nhunterjoe]

Have a friend with a 68 dart. Has a 500" stroker. Cant recall if it is a 400 or 440 based build. Has a respectable solid cam in it. Cant recall exact specs but i will find them. Long story short here, it has a built bittom end and he stuck bone stock 906 heads on it for the time being. It runs 11.20s in the dart.... when tbe 440-1s and mated intake go on it i suspect low 10s.

[firefighter3931]

That cam will require mods to the factory heads. You will need to trim the valve guides down, install the viton seals and use the appropriate dual valve springs. You will also need adjustable rocker arms. The stock valvetrain will not work with a cam that has that much lift. 

With a Stealth head you can get away just swapping out the valvesprings and have them looked over for guide clearance and get the shop to do a descent valvejob. Power will peak fairly low (under 5500rpm) with the unported Stealth heads but it will make some pretty descent torque and respectable horsepower. I would say it would be in the ballpark of 500hp/600tq with a set of long tube headers, descent exhaust system and good intake manifold/850dp carb. 

An old School Holley Street Dominator or Edelbrock TM6 low rise single plane intake manifold is what I would use on a build like this. 

Ron

[BSB67]

So I'm starting to put a motor together, a 400" out to 500" using the 4.125 crank and 4.382" piston 440 source kit. I'm using the standard stealth heads, unported, and will at the very least change the locks for the valves. I have 2 cam choices, a 484" lift Grandma cam or the big comp cam - XE295HL-10. Would the bigger cam be too big for a street motor? I'm guessing it won't but I want to be sure. I'm kinda hoping the extra cubic inches will chew some of that big cam up and make it a bit milder. How should I expect to behave also with the heads unported? Too restrictive for it do you think?

I've debated on commenting.  Well here I am.  Call Dwayne.

[Aussiemadonmopars]

Cool. Thanks for all the feedback. I'm going to go with the stealth heads and change out the valve springs with the ones they recommend for cams over 510". Looking at using just a 1.5 rocker ration though. Can I use a 1.6 ratio? I have some on the shelf I can use or would I best not risk it on these heads and valve springs? I'm going with a full TTI exhaust with the 1 7/8 tubes and 3" pipes, manifold will be an M1 single plane I have on the shelf and probably a spare 750 Holley for now while I get the car back on rego again. The cops here do the licensing and registration inspections so I'm kinda hoping I get the older guy who can't find his glasses and is hard of hearing. I don't want to give him a heart attack when he squeezes the gas pedal either.