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dougman

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Ok i i bought my 73 duster with a 318 bored 30 over with 360 heads and i would say a mild cam.This winter i would like to take the engine out and go over.What do i have to do and what parts do i have to get to get the max horse power out of it ??? I never really built a engine but it's time to learn.I will have about $2000 to play with for engine parts so what can i get to reach the max hp.
 
2 books. Ome to mind in whi h it is in my opinion a must have for a new guy building engines. First, "How to rebuild my small block Mopar" followed by, "How to hot rod my small block Mopar" will show you how to do what you want to do.

IMO, 2K might not be enough.

Also, Max HP may not be what you want unless you car is equipped with a high gear ratio and will use a high stall. Converter.

Things like high compression pistons and large cam shafts. One into play for high HP engines and contribute to less street-ability. Your also limited by a stock cylinder head.
 
"Max" HP for a stock block 318 is probably 550-600. I don't think 2K is enough.
 
Max HP for your budget would probably be a magnum head upgrade to your rebuilt bottom end. Would raise your compression considerably over the large combustion chamber 360 heads on the motor now.
 
I agree with the magnum head swap comment thats probably the best bang for the buck thing you can do. Their cheap and plentiful in junk yards and only require new gaskets push rods and lifters if you dont have them already but if its an aftermarket cam you prolly do. Also youll need magnum head bolts and a magnum specific intake
 
The first thing I would do is familiarize yourself with the term compression height. This is the distance between the piston pin center and the top of the piston. Most 318 stock pistons are in the 1.74" range putting them "down in the hole" quite a bit, keeping compression low. By adding a large open chamber unmilled head lowers it even more. I recommend budgeting first for pistons, rings, bearings and block machine work. When removing the cam and lifters, keep them in order for possible reuse if it is a decent cam. Some money for freshening up the heads and at that point if money is left other things can be considered. Don't forget cam and heads can be upgraded later if funds come available.
 
dougman said:
Ok i i bought my 73 duster with a 318 bored 30 over with 360 heads and i would say a mild cam.This winter i would like to take the engine out and go over.What do i have to do and what parts do i have to get to get the max horse power out of it ??? I never really built a engine but it's time to learn.I will have about $2000 to play with for engine parts so what can i get to reach the max hp.
Click to expand...
You really need to tear it down first.What Intake is on it now?
Maybe the heads have all ready been milled to get you some compression...need to cc them !!!
You could go with pistons like a set of flat-top KB pistons (PN KB167) and have your 360 heads re done and save you some money....This would be doable in your budget !!!
Here is a link to a 360 headed build:
http://www.popularhotrodding.com/eng...ine/index.html
Or basically the same motor build with magnum heads here:
http://www.popularhotrodding.com/tech/0810phr_chrysler_318_engine/viewall.html
Both would get in the 400 hp range...
Check out the racer forum and their are several 318's not much more than stock that are running respectable times with the proper suspension mods.
Before you decide what to build ,you need to tell us your intended goal...Street ? Strip ?...
Martin
 
Since he needs to rebuild the engine first, that is how I read it at least, a Magun head swap is OUT! He already has 360 heads, so he is OK there.

IMO, he should first figure out what slugs he has and at what. O
Compression height it is at. Perhaps there is a slug replacement cost coming up
IMO. A set of KB forged high comp. slugs should be used with new and better con rods. Better to have a strong foundation for a start.
 
I assumed already rebuilt as post said .030 over with 360 heads. If the pistons have a higher deck height and possibly zero decked then the 360 heads are fine. If you believe the motor is not that powerful then it could be you have stock replacement low compression pistons in which the 360 heads are killing what little compression you have. Without knowing what the parts were used in the rebuild you are going to have to take it apart and figure out what you have before buying any parts.
 
I think you should familiarize yourself with everything. Comin on here and saying stuff like "max hp" shows that you really don't know a lot of what you're talking about.....and I'm not trying to insult you. We all had to start somewhere. I say follow rumblefish's advice FIRST. Buy those two books he recommended. Learn the terminology. That way, when somebody recommends something, or tries to sell you something, you'll know if they're a shitblower or not and stand a better chance of not gettin ripped off. I agree with raising compression and the head swap is probably the cheapest way. 302 LA heads or the Magnum heads are both good choices. The LA (Lightweight A engine) heads have the shaft mounted rockers, all on a common shaft, while the Magnum heads have rockers mounted independently of each other with bolts. There are advantaves and disadvantages of each. Read about them, ask questions and decide which you like best. I like the LA shaft mounted rockers best, BUT I happen to be building an LA short block 318 with Magnum heads. Everything just fell together and it was the cheapest thing. Right now, budget is critical for me. There are lots of knowledgeable people here that are more than willing to share that knowledge. But like I said, before you spend big money, spend some small money on books. Rumblefish gave you the best advice so far. I'd use it.
 
i found out that the pistons are flat top with valve releifs the compression is about 8.5 to 1 and the cam was a federal mogal don't remember the specs on the cam. I know i can tear down and rebuild the engine i have done two slant 6 but only stock i went to the parts store and told them i need everything to rebuild it.I have the basics i just don't know all the specs of alot of the stuff.I do thank you all for all the help.The books are a great idea but i just dont have the time to really sit and read them being a single dad of 2 and i just adopted my granddaughter and she is only 3 and she love's the blue duster lol any more help or ideas are welcome
 
Do a Google search for 400 HP 318 there like 5 builds all using different heads most are cheap builds, basically 10:1 compression, 268 to 284, rpm intake, 750 holley, headers and make peak power at 6000-6300 rpms.
 
Why do you want to rebuild the engine? Is it smoking or misfiring? Your main obstacle in getting more power is compression. The replacement low compression pistons are flat tops as well as the higher compression kb pistons. You say they have valve reliefs but I am not sure that means they have the higher deck height. Can you get a list of the parts used in the rebuild? If not I would pull a head and see how far the pistons come up in the bore. Without knowing what parts you are dealing with you can only get bad advice. If you are serious about rebuilding an engine I would look for a 360 bottom end, put the 360 heads on it and sell the rebuilt 318 bottom end.
 
A couple of thoughts, drilling from main bearing up to lifter galley with a 9/32" can help 5/16" not needed unless your up at 7000 rpm regularly, a long bit is required. Opening oil passages to 1/2" from pump to filter, from filter to main oil feed up, can help and is just your time in cost. The stock oil pump with correct clearances does a great job as is, HV pumps will need a larger pan capacity. If you stay with the stock pan an acceleration and decelleration baffles are a must, easily done with your own time and great insurance.
 
The guy i bought the car from said the 360 magnum heads won't work the bolt holes don't line up on the block
 
they bolt right up. The intake bolt angle is different, You need an Magnum intake
 
Intake bolts wont line up but head bolts shoulddnt be any issue that i know of? Intake bolts on a magnum are verticle and not angled
 
If the engine is still in the car do a compression check, and leak down check.
This will tell you what condition the engine is in.
Not much money spent even if you have to buy the tools.

Also good on you adopting your grandchild, me and my wife are raising a 2yr old grandaughter, it is rough some times but the grandaughter is better off with us.
 
ok that sounds good about the magnum heads i just need the magnum intake also. Yes sireland67 i hear you there about raising the grandkids and its hard when your own kids don't do right by there kids.You can only look the other way so long and i could not look away no more no child should ever live a bad life like she had
 
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