75 440 and power questions.

[SandDiesel]

Came across a decent deal on a rebuilt 75 440 and I'll get to that in a sec. Looking for a little education on these so bare with. The 70's stock motor was neutered down to 270HP or so but how it was is what I want to know? Small cam, restrictive exhaust and intake? Can you build these into a decent mid 450hp motor? Heard much higher and you need a forged crank.

The motor I picked up has the following specs
Block is 4006630-440-7 built 17 * 7 * 75 and bored .030 over.
Crank is cast.
Heads are 4004852's, non ported with stock ratio alum roller rockers.
Comp Cam XE268H-10 .477 in/.480 ex, dura .050, and 110 lobe sep.
Edelbrock Performer intake and 1411 carb.

The guy the had it built just wanted a strong and solid driver. I have almost all receipts and it was built by a reputable race shop. Does anybody's best guess put this in the high 300hp's or break into the low 400hp's?

Thanks anyone.

 

[1badgtx]

If you change the heads you may have something...That motor is starving for air..You,ll just have to watch the rpms because of the cast crank will start to flex and wander!!!
Petty Blue 67 GTX:icon_axe::icon_axe:

 

[olebrowndodge]

i built a 75 model 440 , according to the guy at the machine shop i have around 400 hp, cost was around 2600.00 for all parts and paying machine shop for head and block work, i put it together myself and it really runs out very good , lot of power

 

[wingcarenvy]

The year in which a 440 is made doesn't really make a difference since most rebuilds replace all the crappy parts that make smog era 440s weak. The key parts are which cylinder heads it has and how much compression it has. Cast cranks are good to 600hp. I have never heard of that casting number for the cylinder heads. Either way most 440 heads are decent enough to make 400hp and some are better than others. With unported heads its pretty easy to make 400hp. We need more info to make a guess about how much this one makes.

 

[SandDiesel]

Below is from Mopar Muscle on the 452 heads. There is some potential with them.

"On the exhaust side, the 915, 906, 346, 902, 975, and 452 all featured the same basic port. As a result of the need to run unleaded fuel, retrofitting to the late 452 heads, with their induction-hardened valve seats, became a popular swap on earlier engines. Interestingly, the 452 gained a reputation as a desirable performance head casting; through experience, Mopar enthusiasts discovered the performance was on par to that of the esteemed 906 castings of the musclecar era."

http://www.moparmusclemagazine.com/techarticles/5115_cylinder_heads/index.html

 

[wingcarenvy]

Below is from Mopar Muscle on the 452 heads. There is some potential with them.

"On the exhaust side, the 915, 906, 346, 902, 975, and 452 all featured the same basic port. As a result of the need to run unleaded fuel, retrofitting to the late 452 heads, with their induction-hardened valve seats, became a popular swap on earlier engines. Interestingly, the 452 gained a reputation as a desirable performance head casting; through experience, Mopar enthusiasts discovered the performance was on par to that of the esteemed 906 castings of the musclecar era."

http://www.moparmusclemagazine.com/techarticles/5115_cylinder_heads/index.html

Okay, I thought that was a typo in your first post. 452s are great heads. Even if you dont port them they are easily capable of 450hp. Soit looks like you have a plan now. Go for it.

 

[Meep-Meep]

You probably don't have enough compression to take full advantage of that cam. You need to know what pistons you have (compression distance).

 

[kjalltrac]

You can read about my 440 build here http://www.forbbodiesonly.com/moparforum/showthread.php?83686-440-budget-build-what-do-you-think
Pretty much like yours but I have template ported the 452 heads and I also did back cut the valves. I also milled the heads about .04" I´ve got a wopping 8.5 comp by doing the mill. This with stock waaayyy down the hole pistons. The chamber cc is about 76-78cc after this cut.
I also running about 2 steps bigger cam than you do.
I believe my engine has about 380-410hp.

The mid 70s 440 was rated at about 195-225hp I believe, with a comp below 8 (mine was 7.8).