408 Stroker on the Dyno (Finally)

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64ValiantConv

64ValiantConv

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Finally spent some time at the dyno... for anyone interested, here are the specs/numbers:

1973 LA 360 block, .030 over
Eagle cast crank, 4" stroke
Eagle I-Beam rods
Mahle stroker pistons, coated, 447g, flat top
Compression 9.8:1
Heads Edelbrock closed chamber 65cc, mild port matching
Cam - I forgot the cam card at home... something like .484/.492, .238/.242 @ .50, 108LSA, advanced 4 degrees. Hydraulic flat tappet.
Harland Sharp roller rockers
Torker II intake
dyno carb, Holley 750
dyno headers, 1 7/8, non-step headers

I'm going to be running the FAST EZEFI multi port fuel injection, but for the dyno we just used the dyno shops dyno carb.
 

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I would think that compression would be around 11:1 or more with flat tops and 65 cc heads?
 
340sFastback said:
I would think that compression would be around 11:1 or more with flat tops and 65 cc heads?
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Yes you would be correct. I don't have exact everything but it is probably at least 1 point higher than what is thought.

That cam seems really small to me also like at least .100 less lift not to mention the @50 number, especially for a stroker. If the OP can find the cam card he should post it up.
 

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flat top mahle pistons..SBM460030F05 447 grams....1.46 compression height.

70 cc 11.0
65 cc 11.7
60 cc 12.4

that is from mahle catalog
 
The engine could definately use a bigger cam especially with that high compression. A lot of power left on the table there.

That red convertible sure is pretty.
 
Here's a picture of the cam card...

I suppose I might have left some horsepower on the table, as you say. With a 3000lb weekend cruiser I'm not too concerned about it. I'm really wanting good drivability and street manors.
 

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My Mopar bud Max ran his engine the same day. Same engine, cam, pistons, intake, oil pan, but he has a Mopar cast crank, stock 360 rods (narrowed) and RHS closed chamber LA X heads with 1.92/1.60 no mods. Same dyno, he pulled 425HP and 475 torque. We were expecting his motor to pull more than mine due to the things we've read about the RHS heads.
 
Why? The RHS head with that valve flow/works similar to a 2.02 ede with no work.

Small cam that doesn't really use the upper flow potential of the heads. Nice solid street builds that probably idle really nice.
 
"dyno headers, 1 7/8, non-step headers"


Any idea what those headers are? They look like they might suit my non A-body application. Or at least be close enough to offer a good starting point.
 
I agree. I couldn't think of that name when I was replying.
 
awesome.. lookin to build a 360 next summer.. how much about was that build? probably do the same as you have just different heads
 
Engine builder said I have 11:1 compression. I had it confused with my buddy's RHS build compression.
 
Hopefully you have 93 octane in your area. Probably have to retard the timing a little or mix in some race fuel. Any reason he went with such high compression for a street engine?
 
It ran fine with 93 octane on the dyno, hopefully will behave well on the road with 93. 93 is available just about everywhere in Dallas. I don't know why my (ex) engine buy went with higher compression. He said it would handle it with aluminum heads. Then again, he also selected a cam that wasn't so perfect for fuel injection. I'm thinking about changing it out to get the idle vacuum up from 10cfm.
 
He is right that aluminum heads are more tolerant, that is true, but for what you are trying to do he should have gone with step dish pistons. You will probably want to stay with a high duration cam to bleed off some of that cylinder pressure. If you put a milder cam in there your dynamic compression will go up then you will need race fuel. I would run it as is.
 
340sFastback said:
He is right that aluminum heads are more tolerant, that is true, but for what you are trying to do he should have gone with step dish pistons. You will probably want to stay with a high duration cam to bleed off some of that cylinder pressure. If you put a milder cam in there your dynamic compression will go up then you will need race fuel. I would run it as is.
Click to expand...

True, but switching to a cam with the same lobes and a wider lobe sep, maybe installed straight up, would bleed off some of the squeeze.
 
MoparAnglia said:
True, but switching to a cam with the same lobes and a wider lobe sep, maybe installed straight up, would bleed off some of the squeeze.
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true But I like the tourque numbers where they are especially if he can get the same gas that it wan on the dyno with, Maybe if anything retard the cam 1or2 degrees to move the power band up, Run a loose converter as to not load the motor to early and leave the timing where it is. That car will be an awsome rolling burn out machine.

Joe
 
That intake isn't the best. Why get F.I. carbs can work really great and its cheaper to tune.

A old Holly strip dominator intake manifold and a 850 dp would likely make more hp over f.i. Now for the street a newer RPM intake and a holley 750 carb would be the way to go. I would spend the money on a custom carb and forget F.I.

with aluminum heads that compression is perfect, a little racing fuel sure would not hurt thou
 
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