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  #1  
Old 07-22-2003, 10:58 PM
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Moulder Moulder is offline
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Default Please help me build my Hemi (very long)

As soon as my funds are transfered to my checking account I will be purchasing a new hemi block. This will be my first car engine that I build (a hell of a first isn't it). I have built some tractor engines so I know a little bit about building engines. I just want to get all the input that I can. Right now I am just focusing on the short block assembly, or rather the parts to be able to put a short block together. Here is some facts about my car to help you pick the parts I need.

The car: is a 1970 Plymouth Barracuda. It is currently a 318 automatic car. It has power disk brakes in front, ac, and ps.

Suspension: all new pollygraphite boushing, new mopar performance big block springs, new kyb shocks at all corners, the largest front and rear sway bars I could get from PST, still has the 318 torsion bars up front.

Transmission: I have a complete 4 speed set-up to swap into it. it is a 23 spline 833

Rear axle: 8 3/4 with sure-grip and 323 gears.

Crankshaft: I have an Eagle forged 4.150 stroke crankshaft already.

The car will be mainly used for show and cruise. I want to be able to run 92-93 octane gas. I plan on using Mopar Performance aluminum heads.



Now what rods, pistons, bearings, oil pump, harmonic blancer, ect., and what machine work should I have done to it. The block I am buying is Mp# 5007668 finish bored at 4.25". I want good relibable parts, but I am not build a top fuel motor.

One more question would these rods be a good low cost but reliable choice, or are these a big no-no?

http://cgi.ebay.com/ebaymotors/ws/eB...tem=2424744074
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Old 07-22-2003, 11:11 PM
Blygy Blygy is offline
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Default Rods??

Who built the rods.. I didn't notice a manufacture name...other than "Same as Eagle rods but priced several hundred dollars less."

sounds to good to be true to me.. Why are they several hundred less???

I always tell my wife "There is a big difference between cheap and inexpensive." You need to decide if these are inexpensive or just cheap..

My .02

Blygy
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Old 07-22-2003, 11:44 PM
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Those rods are 6.9" and a .990" pin. The length and the pin are not stock dimensions. Just as long as you know this when buying pistons. I can get eagle rods for the same price or very close. If your going with an aftermarket rod i would go with the 7.1" rods if your running the 4.15" crank. That will give you a little better rod ratio and a pin height of around 1.54" or so depending on how much is cut off the deck.

On the block i recommend doing all the machine work from modifing the oiling system, line-honing, squaring the deck, boring and honing. I wouldn't recommend buying the block finished honed.

You need to have someone with experience building hemi's do this. If your going to spend that kind of money make sure you only do it once.
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Old 07-23-2003, 01:21 AM
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Replace that 8¾ rear with a Dana. A properly built Hemi backed by a 4-speed will shred that 8¾ on the first launc
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Old 07-23-2003, 01:28 AM
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I can't tell you much about your motor, as I have only slobbered on them at car shows.

But, I would chuck the 318 torsion bars and go to the .92" bars.
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Old 07-23-2003, 08:51 AM
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The two choices of rods that I was considering was Eagel 3d rods or Manely h-beam. I think I would go with a longer rod and a .990 pin and a light weight piston (which one though?).

Hedgehog: when the mopar performance cat. refers to finished bored to 4.25 does this mean honed also?

What is everybodies preference on engine bearings?

What I am realy looking for is a run down on how you would build a hemi short block if you were doing it, what machine work you would have done, and for the same application.
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Old 07-23-2003, 10:54 AM
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Geezer Geezer is offline
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Thumbs down "Just like", except less $$??

These are most likely off shore rods from China. [or worse] I would think they would need AOT of checking, re-machining, etc to be useable. Then, the question is posed: What are they really made of??? Just because the mfgrs throw around phrases like "4340", "aircraft quality", etc, does not mean the material is suitable for a performance engine.
Next, as already pointed out, they are "bastard" dimensions...Custom pistons are a requirement.. Protracted delivery time is a sure bet.

As for the Manley rods.. I'd use them, or Crower. I would also use the "I" beam vs the "H" beam. I'd do that as the "I" beam is inherently stronger because it keeps the mass of the beams as far from the centerline of the load as possible..

Furthermore, honing w/ a deck plate is a necessity.. Not alot of shops have the plates.. Might want to check first, B4 you lay out your $$$.
Just my $.02 worth.

Back to working on my 528!!!
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Old 07-23-2003, 07:20 PM
vanishPt vanishPt is offline
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Moulder, are you inclined to buy all of the parts new, or would you consider used?
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  #9  
Old 07-23-2003, 10:56 PM
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vanishPt: For the most part I think I will use new parts. They are just that new parts not something that has been in someones road warrior. I was looking a used engine block untill the seller put in on e-bay (I just happened to find it listed on there one day). Hemi parts are almost the same price new or used. I am open minded though, what do you have?


I need to know quickly if I would be better off with engine block # P5007668 finish bored at 4.25" or # P5007667 rough bored at 4.19". Summit sent me an e-mail about a 10% discount, but I only have a week to use it.

I would still like to hear some hemi build-ups and what parts were used (of the 472 variety if possible).
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  #10  
Old 07-23-2003, 11:20 PM
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Moulder,

You might want to take a look over on the Drag forum, Hemi vs Wedge thread. Steve 1118 has a couple of pretty good posts about his combination, and even though its a bracket motor, believe there are some things you could incorporate into your setup. BTW I believe finished bored is within a couple of thousanths, can't imagine the block coming with a final hone, not knowing what kind of ring package is going to be used in the block. Unfortunatley MP has been known to do some screwy things in the past so I believe you'd be wise to wait until you could physically measure the block before you got pistons for it.
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  #11  
Old 07-24-2003, 12:04 AM
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Clevite bearings, use nothing else. You'll need the performance ones because they have a radius relief to clear the radius on the crank.
Most (most) pistons are designed so that when the cylinder is honed to a nominal size(4.25", standard bore in this case) the piston will have the minimum clearance that the manufacturer recommends. For example; say you buy a piston with a recommended minimum clearance of .005". Then the piston skirt size where the manufacturer recommends that it be measured will be 4.245" for a 4.25" nominal bore. Not that all pistons are run at minumum clearance. You have to have a minimum of .002"-.003" before final size for torque plate honing. The blocks are not torque plate honed so depending on the piston you buy you may not have enough material left to use a torque plate. Also, i line-hone all (new and used) blocks to make sure they are straight, round and have a good surface finish for good heat transfer. The deck is then squared and the cylinders are bored(not honed) off of the deck so they are perpendicular and parallel to the main line. Then they are finished honed.
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  #12  
Old 07-24-2003, 12:49 AM
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23T-Wedge & hedgehog: I read Steve 1118 post (Hemi vs Wedge) and it does make some vaild points. Would I be better off modeling my build-up after a mp crate motor? Use aftermarket rods (stock length) or stock rods and use a piston that will give me a 10.5 compressin ratio since I plan to use aluminum heads? I think that useing stock parts and keeping it simple makes the most since in my case.

I still have the question of which block, can anyone help me out here?
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  #13  
Old 07-24-2003, 01:01 AM
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I would run the 10.5 compression with the aluminum heads. As far as rods or pistons it really doesn't matter in your case. Its not a race car you will not notice any difference. I wouldn't be too concerned about super high strength or light weight parts because you will never push the engine enough to require them. The stock rods are pretty strong. I would concentrate on good machine work. I don't know what the difference in prices are between the finished and unfinished blocks but the unfinished block will probably cost more by the time the machine work is done. You want an engine that will last, you always have to start with good machine work regardless of the intended usage or power output.
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  #14  
Old 07-24-2003, 06:30 AM
vanishPt vanishPt is offline
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I know that you said that you do not want to buy an engine. add up all the parts and see if this interests you. You will need to freshen it up. I tried to email this to you but your email is not listed.
http://www.moparts.org/ubb/Forum14/HTML/000195.html

look for my post
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