Dan the man
Well-Known Member
A stroker crankshaft would be a whole lot simpler
LA 318 advice
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Baggs
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Baggs
Well-Known Member
Also, I thought I mentioned it here, but square and 9.575 /9.58 DH. Will be around 8:1 SCR. A man has to rein it in some times!
On the 318, the LA crank IS the magnum crank.
Same exact #3751841 casting number for both
PRH
Well-Known Member
^^^^^^^^
Lol…….318 mafia in the house !!
Lol…….318 mafia in the house !!
Road Grabber
Well-Known Member
I had a lot of success getting more out of a 1970 318. I didn’t go crazy because there wasn’t much out there like today. A few things worth mentioning:
You mentioned using your heads. Take an intake gasket and exhaust gasket. scribe the ports. 318 engine heads are sloppy. If you’re not in a hurry and into it port your heads with a set of carbide rotors filed. This was a huge improvement.
I used a 273 four barrel carb. It worked great out of the box. Dumping big carbs and cams in a 318 is in my opinion a waste without heads that can flow. OR better yet slap a set of 340 or 360 heads on if you have them. Dodge vans had 318 engines with 360 heads. Chrysler did this and it worked great.
Without mentioning a bunch more I think balancing an engine even stock is worth it. Chrysler was not great at tight specs balancing their engines so it would be an improvement no matter what.
You mentioned using your heads. Take an intake gasket and exhaust gasket. scribe the ports. 318 engine heads are sloppy. If you’re not in a hurry and into it port your heads with a set of carbide rotors filed. This was a huge improvement.
I used a 273 four barrel carb. It worked great out of the box. Dumping big carbs and cams in a 318 is in my opinion a waste without heads that can flow. OR better yet slap a set of 340 or 360 heads on if you have them. Dodge vans had 318 engines with 360 heads. Chrysler did this and it worked great.
Without mentioning a bunch more I think balancing an engine even stock is worth it. Chrysler was not great at tight specs balancing their engines so it would be an improvement no matter what.
Some stroker cranks come with 2.0 inch rod journals. The handful of pistons for an LA with.927 pin diameter that I’ve seen recently come within a few thousandths of zero deck with 6.2 or 6-1/4 length sbc rods. If someone was especially Spend happy, it’d be interesting to see what a stock crank could be offset ground to for the Honda rod journal (1.89) rod journal (even eagle makes rods for the sbc to run Honda journals), but it’d probably cost a blind fortune in Mallory metal to balance it.
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Baggs
Well-Known Member
I have a few small Holley”s. 450 and 550? CFM as I recall. I forget which is square bore and spread bore.
I sent payment out today for a 318 Streetmaster intake. I know they work well on mold sbc’s, will look better than a performer, etc.
I will have to now think of balancing the rotating assembly, didn’t occur to me. And the cost isn’t a deal breaker either.
But will still be an 8-1 SCR engine, so $$ to stroke it, offset grind the crank, etc are not in its future.
Thanks
I sent payment out today for a 318 Streetmaster intake. I know they work well on mold sbc’s, will look better than a performer, etc.
I will have to now think of balancing the rotating assembly, didn’t occur to me. And the cost isn’t a deal breaker either.
But will still be an 8-1 SCR engine, so $$ to stroke it, offset grind the crank, etc are not in its future.
Thanks
Baggs
Well-Known Member
Can’t edit a post, forgive my spelling mistakes.
junkyardhero
Well-Known Member
the street master only came in square bore for the small block. also, the entry is really confined so check your throttle blade clearance. i know it'll work with a 625 afb, but i don't know on the holley.
if that holley 550 has 1 9/16" bores then you're golden
the street master is satisfactory for a low compression 318. they're small port runners and tiny little plenum. great throttle response but they're cooked by about 4500rpm. fine and dandy for a cruiser.
that said, a performer will do everything a street master will do, only better and pull to 5500
Baggs
Well-Known Member
Good info. And matches up to the cam I’m considering. 262 grind from comp. I’ve really lowered my thoughts and expectations on this engine. Sorta looking at it in a realistic way, not like I would have 40 years back.
And older (not old) dog has to get smarter
junkyardhero
Well-Known Member
Good info. And matches up to the cam I’m considering. 262 grind from comp. I’ve really lowered my thoughts and expectations on this engine. Sorta looking at it in a realistic way, not like I would have 40 years back.
And older (not old) dog has to get smarter
this one?
DODGE COMP Cams 20-222-3 COMP Cams Xtreme Energy Camshafts | Summit Racing
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the only thing i like about that cam is the 110 LSA. more lift and basically the same duration as a 340 cam? pass.
not a great match for low compression, street master and a small carb.
Baggs
Well-Known Member
Bigger than I was looking at. Hang on a bit.
Baggs
Well-Known Member
Baggs
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But dang, didn’t notice the LSA. Gotta refigure a new plan.
junkyardhero
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better, than the first one. it's similar to an old MP grind (a little less duration on the intake) which is cool. it can make some power with the right supporting cast.
Baggs
Well-Known Member
You feel 110 LSA for a low compression engine would work, or lose the bottom end?
junkyardhero
Well-Known Member
yes! a tight LSA is going to promote bottom end torque and midrange with a sacrifice to idle vacuum, which can possibly result in fickle street manners-- this is generally in more radical instances like, say below 108.
but i wouldn't hesitate to run a 110. and on a small cube motor with low compression i'd much prefer it over the typical 112~114's that are generally offered.
I wouldn't cam or lifters from Comp. They've had issues with wiped lobes and crappy lifters for a long time now.Good info. And matches up to the cam I’m considering. 262 grind from comp. I’ve really lowered my thoughts and expectations on this engine. Sorta looking at it in a realistic way, not like I would have 40 years back.
And older (not old) dog has to get smarter
108 better and 106 better still, but 110 "will work". Hell 115 will work, but you're leaving a good bit on the table then. Enough to argue over.
Call Racer Brown cams and get a custom for your combination. 410 866 7660. Their cams are not that much more if any. I would not run a Streetmaster intake. Why limit your rpm to 4500?
It's mainly about when the intake valve closes which tighter lsa and smaller duration both move the intake valve closing earlier generally will have better bottom end. Tighter lsa and larger duration will increase overlap which gives a rougher idle. But a small cam with a tight lsa generally gives a moderate amount of overlap, since smaller duration shrinks the amount of overall overlap.
Overlap is the greyed out triangle in between. Moving the lobes closer together (tighten lsa) and or increase duration gonna increase that overlap triangle, rough idle.
If you say keep lsa at 108 then decreasing duration will be the only way to reduce overlap which is basically what you want small ish cam on a relatively tight lsa. Earlier intake valve closing point.
If you say keep lsa at 108 then decreasing duration will be the only way to reduce overlap which is basically what you want small ish cam on a relatively tight lsa. Earlier intake valve closing point.
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Baggs
Well-Known Member
Thanks all, for some reason I’m not getting notices when a new post ilis added.
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