moparstud440
Well-Known Member
Compression is what stands out to me as holding back some hp. For a street car it sounds like a very nice engine. Everyone always wants more hp, but how often in a street car do you use all the hp anyways?
Only 460hp
- Thread starter srduster340
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Yeah that's the first thing I'm addressing. Brian Haflinger from IMM engines commented I could raise compression to 10.2. I'm gonna take his advise. Trying to find flat top pistons with the correct cc's is an issue. Trying to avoid a running another dish.
John S
Member
Having done a 416 stroker strictly for street driving, your numbers do sound low. You have a larger cam, carb, rocker ratio than my build. Take a look at my build and maybe something comes to mind... Like the heads? Good luck!
I updated this with a new link to YouTube for the dyno test:
And here are the full specs:
Finished a 416 stroker last month and made a little video. Thought you guys would be interested also. This is a 100% street motor so I told engine builder to build it for low RPM driving. I wanted a decent idle and lots of grunt under partial acceleration. 340 block 30 over, Trick Flow 190’s no extra work, Scat rotating assembly, RPM Air Gap, Harland Sharp Roller Rockers 1.5, MSD RTR, 750 Holley Vac Secondary, Icon IC 745 pistons, final compression 10.1. He had a Comp Cams Mutha Thumpr (.522 In, .509 Ex, 235 In, 249 Ex, 107 sep) on the shelf so we decided to try that. I know it gets a lot of negative vibes and I felt that way till I saw that Joe Sherman had used them and was impressed. I asked the builder (Bill @ RAM Engineering) what he thought when we ran and he said he was surprised too; the numbers were respectable. The idle is noticeable but as soon as the RPM comes off idle, it smooths out quick and we were making 400 ft lbs torque at 2000 RPM. 524 ft lbs at 4600 RPM. 503 HP at 5700 RPM. Should be a fun driver when installed in my 3200 pound Duster.
I updated this with a new link to YouTube for the dyno test:
And here are the full specs:
Finished a 416 stroker last month and made a little video. Thought you guys would be interested also. This is a 100% street motor so I told engine builder to build it for low RPM driving. I wanted a decent idle and lots of grunt under partial acceleration. 340 block 30 over, Trick Flow 190’s no extra work, Scat rotating assembly, RPM Air Gap, Harland Sharp Roller Rockers 1.5, MSD RTR, 750 Holley Vac Secondary, Icon IC 745 pistons, final compression 10.1. He had a Comp Cams Mutha Thumpr (.522 In, .509 Ex, 235 In, 249 Ex, 107 sep) on the shelf so we decided to try that. I know it gets a lot of negative vibes and I felt that way till I saw that Joe Sherman had used them and was impressed. I asked the builder (Bill @ RAM Engineering) what he thought when we ran and he said he was surprised too; the numbers were respectable. The idle is noticeable but as soon as the RPM comes off idle, it smooths out quick and we were making 400 ft lbs torque at 2000 RPM. 524 ft lbs at 4600 RPM. 503 HP at 5700 RPM. Should be a fun driver when installed in my 3200 pound Duster.
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Locomotion
Well-Known Member
SRP, Probe, KB and possibly a couple other manufacturers make/made nice, light flattops. Problem might be price and availability. Just gotta shop around.
autoxcuda
Well-Known Member
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I'm not absolutely certain on this, but from what I've read you're looking at 3-4% per point of compression. So going from 9 to 10:1 is going to net like 20 HP. Is that your expectation?
What are you doing about head and cam, while everything is apart? I think these are the problem areas.
What are you doing about head and cam, while everything is apart? I think these are the problem areas.
John S
Member
Probably because it's a group you have to join. I'll screen shot the info later. Thanks
John S
Member
I updated post #78.
sorcerer
Active Member
Heads are the culprit; way more than compression.
Awesome numbers.
I agree. Not enough port volume or air flow. When I gathered parts for this engine a standard stroke 360 was the plan. Then Mopar released the stroker crank & me being a torque freak I grabbed one.
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According to Brian Hafliger at IMM my cam is not the problem. He's made 500hp with smaller bumpsticks. More compression for sure. I want Trick Flows. The HS rockers are required with Magnum heads due to oiling but is "recommended" with LA style heads. I'm gonna just bite the bullet & buy them.
7e5hangten360
semi-pro
i think that if you want to go from 460 hp to 500 in a single step without touching the short-block, you need to up-grade to a street-roller. have a look at the xr series of comp cams. lifters are a pita to install though. you would need to grind the block for lifter installation. also, a switch to a single plane intake would be a good move while it is removed. if you want to change the pistons, srp has a 16.9 cc dish piston. going to a flat-top would mean too much compression ratio for the street. also, if i was you and wanted to switch heads, i would have your current ones flow-tested before making the move. they might be better than expected.
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Getting the heads flowed is probably what I should do before I spend Trick Flow money. I am finding that trying to run a flat top is way too much compression. I want a piston that will work with open or closed chamber heads. I do have a single plane intake. Think it's a Eddy Victor. A 248/254 street roller sounds interesting.
Rat Bastid
Dunamis Metron
Don’t buy a cylinder head based on airflow. That will send you down the river right quick.
What's the formula to determine cross sectional area needed for a given cubic inches and rpm? Didn't know this when I ordered the heads way back in early 2000's.
Given readily available cylinder heads out there, and the fact you're running a stroker, you'll be hard pressed to go too big in the head.
Trick flows are quite an investment requiring specific rockers as well.
What is your goal, power wise?
I would not go smaller on the cam. That big engine needs the big cam.
Trick flows are quite an investment requiring specific rockers as well.
What is your goal, power wise?
I would not go smaller on the cam. That big engine needs the big cam.
There are solid rollers available that drop right in no grinding required. Howard’s 91734 as one example (which I am using)
Dropped right in on an early 90’s block.
Howards Cams 91734
These worked without uncovering any of the oil bands? What lift are you running?
Yes. Look at the picture of the lifters, no where close to that happening. I don't have pictures of when I installed them, but that was not an issue. As to how much lift before they might? I have no idea. They were no where near being uncovered in my case. Lobes are .390"
HS rockers are only "required" with Magnum style Trick Flows. That's what their website says. They are about $2500 give or take or few "out the door" at Summit. That depends on which spring/retainer pack you go with.
moper
Well-Known Member
Yup yup. The cams intake lift is around .540 at the valve, and it’s not there for long. If the heads are closer to 260cfm @.550, then the 460 number is close. Also shows why the torque curve is what it is. More cam would help if you wanted more hp. As would a larger volume intake manifold.
Rat Bastid
Dunamis Metron
I have it at home, but you should be able to find that math on line pretty easy.
mopowers
Well-Known Member
Hey moper. Where ya been?? Good to see you back!
moper
Well-Known Member
Thanks. I wanted a break.
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