Possible 451 build options

-
dstan

dstan

Well-Known Member
Joined
Jun 17, 2016
Messages
101
Reaction score
13
Location
prichard, Wv
The 727 in my truck gave out the other day and i am going to pick up a used one and a 400 Chrysler later today. The 71 440 in my truck now is nearing the end of it's life and I am considering either throwing the 400 that I'm getting in the truck when i swap the trannies and rebuilding the 440 or leaving the 440 in it until i have all the other parts ordered and using it's crank, cam, closed port heads, and rods to make a cheap 451.

I need to do this on a budget of about $2000 so i know i'm not going to be setting any performance records. All i know about the 451 is that i will need a special set of pistons and the journals and weights on 440 crank to be cut down.

The 440 that is in the truck now is pretty rough. It still makes good power, but it looks like crap and there is a concerning amount of jb-weld on the bottom of it. The 400 on the other hand looks very nice and was just freshened up with new seals and rings. It's a stock 74 engine other than that.

I'm just looking for input from anyone who has done a budget 400, 440, or 451 build to give me some advise. and where i would get the most bang for my buck.
 
The only cutting of the weights should be for balancing. The two engines use the same oil pan and windage trays. The main journals need turning to size and there is the option of Chevy rod journal size to make a 470....
 
You'll need to cut down the counter weights for block clearance putting the 440 crank into the 400. You can do it cheap with a grinder if it comes down to that. I took .100 off and that wasn't enough. The edges of the CW's needed beveling and the block needed some relief with a grinder. Turning the mains down is essential, doing the rod journals is fine if you have 2.200 rods available in budget. Honestly, unless you have cheap crank grinders about, just buy a new crank, like a Molnar or even an Eagle or Scat.

If you like, I have an old school offset welded factory crank that I collected in some horse trading. It seems it was supposed to be 4.150, but when I put it in the V blocks on the balance machine and measure, it measures 4.10x. Polish's up nice, decent crank from back in the day but still factory low carbon steel. Used with factory heads, should be fine with huge torque. I also have a set of Icon IC 827 pistons for 4.375 bore. Unfortunately the jackass I bought this engine core from used a ridge reamer like a chimp and it needs 4.402" to clean up. So I have surplus pistons and rings. Special order, no return. So add 6.760 rods(you can use the 440 rods) and you can have a 500 inch motor. PM if you're interested, I can balance the assembly if you like. Figure about $1050 out the door unless it needs heavy metal, which I'd doubt. S/F....Ken M
 
While I would love to take you up on that offer i just spent all my money on the new transmission (I'm in college and normally broke), so the rebuild won't happen for a while. Just trying to find the most practical way for me to make the power I want (around 400-450).
 
I'd go with the 400, pull the heads off, bowl port/VJ for 2.14/1.81 valves, throw a decent cam in there with beehive springs and call it good. Similar to this build, but I'd use a cam like Comp XE275HL. You'd need the heads machined for valve seal clearance and a real set of rocker arms would be nice. The Erson/Isky/Crane ductile iron stuff is pretty much ideal for this application and used stuff is often reasonable. I got two sets of used Erson's for $250 off C/L locally, for example. But there's often issues with used parts, which is typically why they're being sold. The Mancini aluminum rockers are a good deal for American stuff.

400 BB Mopar budget dyno test***MORE PICS | Unlawfl's Race & Engine Tech | Moparts Forums

The 71 440 heads would be 346 heads unless they've been changed (unlikely) and therefore the same, performance wise, as any heads that'll be on the 400. No point in changing unless there's been porting done. A lot of the utility in rebuilding iron heads is dependent on the cost of machine labor or ability to DIY. If you're getting charged $700 to redo the factory heads, a set of Sidewinders or 440 source heads is a better deal; they certainly make more power.

I'd toss the 440 cam unless it something aftermarket. Reconditioning rods may make sense, again, dependent on labor costs. You'd need them bushed for a .990 floating pin if you're going to use them for a 451 for most pistons. More money being spent on marginal parts....
S/F.....Ken M
 
The heads on the 440 are not original and neither is the cam. I don't have the cams specs, and i'm not sure what heads where put on it.
The 400 was supposed to be from a 74 New Yorker, but i looked up the code and it's a 76-78 block.
 
I'd just recommend the b wedge 440source crank and pistons be used. Its decent value stuff and it is easy to get together with stock rods ans little messing with th block. I think you will need more than 2k to do a ccomplete job though. You still need basic machining and the wearables and those wil eat up most of that figure on their own.
 
EchoSixMike said:
I'd go with the 400, pull the heads off, bowl port/VJ for 2.14/1.81 valves
Click to expand...
There is absolutely no need to install those valves of a 400" pickup truck engine. If anything it will cause it to fall on it's face.
The 526" we turn 7200 rpms only has 2.14"/ 1.81" valves in it and it only weighs 2000#
Why is it always that everyone wants to over valve and over cam an engine? Answer: Reading to many magazine articles that's sole purpose is to sell parts and machine work for it's advertisers.
If your a poor college kid just keep something in it that runs for now and save your money for an engine later on.
Personally I would keep a 440 in a truck, but if have a 400 go for it.

Tom
 
Big valve heads suck..I mean they blow.....Oh, I'm so confused now. I guess it depends if you're talking about intakes or exhausts

Wait, wait, here's some dyno tests. This is a 440, 1st using ported 346 heads and 2.08/1.74 valves and 2nd the same head and engine after installing 2.19/1.81 valves and blending the seats/throats into the already ported runners.

RPM...................2.08/1.74................2.19/1.81

3100.............444 TQ/262 HP.............435/257
3300..................478/300..................467/293
3500..................496/330..................492/328
3700..................500/352..................503/354
3900..................486/361..................506/376
4100..................482/376..................506/395
4300..................485/397..................497/407
4500..................484/415..................485/416
4700..................476/426..................484/433
4900..................485/452..................491/458
5100..................478/464..................494/479
5300..................486/490..................496/500
5500..................474/496..................499/523
 
There's no reason a larger valve on it's own should reduce flow, at low lift or anywhere else. If people eff up the ports, bowls and/or valve job while doing it, then all bets are off.

Basic 452 head, VJ and bowl work 2.14/1.81, cheapy SS 3/8" stem valves, not nice undercut Ferreas, super easy, blend in the serdi work. Less than a day's work in the shop. SF-1020 at 28inch vacuum.

.050 36.3/30.0
.100 69.7/60.3
.150 106.3/88.8
.200 141.6/115.5
.300 197.7/155.3
.400 231.2/184.1
.500 240.9/205.3
.600 245.5/217.0

There's no reason to increase port volume by doing anything other than opening up the bowls and blending the results in. Huge ports=low velocity which makes for crappy driving. If you're doing some low lift, tall gear/big tire pickup truck stuff then you might even go with a 30 degree VJ to pick up low lift flow since high lift flow means nothing in that case. Maybe this is excessive tech, but IMO, this is stuff any decent race engine shop should be able to do.

231@050 isn't a huge cam, on the big side, but not undriveable.

I'm assuming that this truck is a 2nd vehicle or some sort of 'play' vehicle. If you're slapping **** together on your only daily driver vehicle then discussing strokers, cam swaps and porting is probably the wrong thing to be doing. S/F....Ken M
 
It's definitely just a project/toy. I just wanted something that will go fast in a straight line and could still pull a boat if i need to. The 440's going to be left in it for now.
 
You must log in or register to reply here.
-

Back
Top