NC Engine Builder
Grumpy Old Man
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Your going to be removing all that stuff
Engine is pulled - 273 rebuild or replacement 360 crate?
- Thread starter brodphish
- Start date
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So been a month and now we’re back at it. Final decision is to build the 318 it’s all disassembled and ready to go to the machine shop. On Tuesday I’m going to spec out the engine with the builder and buy the parts. I’ll post what we decide on. The builder thinks we can get over 400hp out of the 318. Fire away!
We strongly considered building the 273 by going .12 over (it’s already .060) and using Chevy 305 pistons. However it turns out there is a cast crank in that 66 block. I was expecting forged. There was also metal debris of uncertain origin in the oil pan.
So best to move on to the 318. I’ll post our spec parts Tuesday or Wednesday.
We strongly considered building the 273 by going .12 over (it’s already .060) and using Chevy 305 pistons. However it turns out there is a cast crank in that 66 block. I was expecting forged. There was also metal debris of uncertain origin in the oil pan.
So best to move on to the 318. I’ll post our spec parts Tuesday or Wednesday.
here's a basic recipe
www.hotrod.com
i'd deviate from that and substitute some type of aluminum head: speedmaster, afr, eddy what have you.
stay in the same ball park on the cam and you'll see at or near the 400 target.
318 Engine Build - A Parts Book 400HP 318
Check out the build of an LA based 318ci engine that makes 400hp on pump gas from Mopar Muscle Magazine
i'd deviate from that and substitute some type of aluminum head: speedmaster, afr, eddy what have you.
stay in the same ball park on the cam and you'll see at or near the 400 target.
The 318 400 build article is pretty much the recipe we were going to follow. Then today we determined the 318 heads were cracked as I understand they pretty much alol are. So it’s on to the aluminum heads unless I buy a crate engine which is looking better and better.
Can the cracked Magnum heads be repaired? I think the 273 heads may be usable on the Magnum block, is this true? Just trying to understand all my options before buying aluminum heads or a crate motor.
Can the cracked Magnum heads be repaired? I think the 273 heads may be usable on the Magnum block, is this true? Just trying to understand all my options before buying aluminum heads or a crate motor.
The magnum block may not have the oil feed to the rocker shaft. The early roller blocks do. But there is a cut off. What year? Someone will.know.
It’s a 1998 Magnum out of a Dakota
PHR will know. I’m thinking that you need a magnum style cylnder head casting. You can oil through amc style lifter (my Howard’s EDM) are oil through capable. But it would seem that the shafts wouldn’t oil enough from splash, only.
don't use the 273 heads on the mag motor. yes, it can be done but it's going backward.
i'd skip trying to repair them and go straight to a set of remans or really, right into a set of aftermarket alumn units.
Today we bought a 360 from the pick n pull. Gonna put the 360 crank in the 318 block bored to 4.06. Got KB pistons to fit the build and a Holley AVS 650. Deciding on a cam and intake in the next few days.
i'm not trying to insult yours (or anybody's) intelligence, but you know that's not a direct swap, correct?
If the heads are good on the 360 we will use them. Otherwise aluminum heads will go on it.
for the other end we found a Ford 9 LSD and bought Moser 3.25 ring and pinion for it. It’s gonna all go in a Moser early A rear housing. Moser assured me no fitment problems with their housing.
for the other end we found a Ford 9 LSD and bought Moser 3.25 ring and pinion for it. It’s gonna all go in a Moser early A rear housing. Moser assured me no fitment problems with their housing.
No insult taken. I’m here to learn. What machining needs to be done? My engine guys mentioned something but it didn’t pick up on it.
360 main journals are bigger than 318, so you'll need to cut those down (and ideally heat treat the crank after, or not). you'll also need to trim some of the counterweights to clear the pistons-- which will need to be custom. though you can run stock low compression 318 pistons they'll wind up something like .06 above the deck.
seems like your engine guy is dead set on building some weirdo combo just cause.
the stock 360 mag will make 400hp practically falling out of bed and take *zero* custom parts or exotic machining.
Thanks Junkyard. I’m gonna talk to him about just building the 360 now that we have it.
FlamesAreWicked
Well-Known Member
Initially I’d say go for a 360 but a warmed over 318 would make life easier probably and you can get 300hp without a ton of trouble. Hell even late 80s roller LA block to start with..
look, i don't know what the situation is but homie seems to just want to go against the grain and get a little different with it, which is fine. i like different. different is cool.
but 360 crank in a 318 is just GOBS of money in machine work: cut the mains on the crank, skim down the counters, cut the rear main down to 318 size too. square and deck the block, align hone the mains. then cut it for whatever oversize. then pistons, whatever they wind up being are likely gonna need fly cut for valve clearance. and with all that, you're probably looking at cutting the heads and the intake to get everybody lined up and happy. then you're into rods-- bolts & resizing, polishing the crank, balancing everything up.
just thinking about that undertaking makes my wallet hurt.
you have other, more viable options available to you that are much cheaper and more approachable: a 390 stroker for the 318 is different and neat. the 360 with heads and a cam would make 400+ all day easy money and not even break a sweat doing it.
65TerrorCuda
Well-Known Member
If you build a unicorn and anything goes wrong, you're up a creek. Just got through undoing that myself and it's an undertaking.
You can build a pretty snotty 360 with flat tops and a SFT cam. The money you save can get you the clutch and differential you'll need.
T-142F LA Solid Lifter Camshaft@Schnidercams 242/242 .510
273 rocker arms and about ..470~480" lift at the valve.
(5800 shift point).
Or, Howards Cams Mechanical Flat Tappet Camshaft; 1964 - 2003 Chrysler 273, 340, 360 2400 to 6200 Howards Cams 710862-08 if you want to run less compression.(5600 shift point).
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