Posted By: razoreyes45k
SB Head Choices - 11/08/12 08:45 AM
What are the Head Choices for a mainly street-driven 340 (422 ci) stroker?
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I should have been more specific but these are my basic parameters:
1. Aluminum
2. Must be capable of flowing enough cfm to support 422 ci (idealy more than 270 cfm after porting)and accomodate a 2.100" Int. valve w/o shrouding.
3. Reliance on stock-style valve-train design.
*** I've ruled out W2's because the engine will be used in either a truck or a van (W2 headers are not designed for use in a VAN/TRUCK. All other Mopar W-Series heads are not considered for similar reasons as stated above. I realize that with the right machining, anything is possible; only, the basic head must provide the foundation to perform the required work to reach these goals.***
{BTW, the 2.100" Intake valve is a recommendation for engines larger than 420 ci and is also supported by the Reher Morrison belief that (52%)(Bore)= Minimum Intake Valve Size. In this case the minimum Intake valve size is 2.132"}.
At this point,cost is second in priority to performance.
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Thank you for posting. I watched the Youtube video and even found another thread from your post highlighting a 620 HP build using Roller lifters on the A Engine.
I remember seeing these Airwolf heads advertised through MCG a while back. I attempted an on-line search for information about them but came up mostly empty-handed.
The dyno-sheet is very impressive for sure. Is there a website with dealer information or even Flow Bench Data and close-up images of these heads ?
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The short block is currently being amassed, but it will have all new 4340 internals with Diamond forged flat tops and Total Seal Gapless Rings.
I'm pausing with cam selection because people have said they have used Roller Cams in A (Pre-Magnum)engines. To my knowledge, a roller lifter link-bar will not clear the block due to the A engine's 59* lifter angle. Although the magazines have published stories claiming the marriage of this combination, I have yet to see close-up pictures and hear explanations regarding the modifications involved to create this. Assuming that much effort is required to fit the link-bars, and not knowing that other people have successfully acconplished this themselves without tapping into water-jackets, I'm inclined at the present to investigate a Hughes Solid Flat-Tappet, slightly longer in duration and under .550 lift using the Chrysler 1.5 RR, suitable with Power Brakes.
The '73 340 block has been sonic-checked and magnafluxed,line-honed,torque-plate honed using 520 finishing stones and the bolts are new MP factory replacements. Surfacing the deck will most likely have no more than .010" taken off. CR is aimed around 10:1 to run pump gas and I'm planning to have a few thousandths Compression Distance to accomodate a closed-chamber cylinder head measuring anywhere between 63cc and 70 cc.
Elsewhere, the oiling system will be modified to flow through the lifters/pushrods. A bigger pan, HV pump, 360* fully-grooved main bearings, Big bottom-feed style pickup and other related mods to safeguard better than OEM oil distribution.
So far, I'd say this will be a solid short-block. I don't know how this engine by design will stand up to the occasional rigors of abuse, but I'm hoping my machining and choice of parts will allow the engine to run a solid 120,000 - 150,000 mainly street-driven miles before it expires.
Depending on choice of Head and Cam, 520-550 Gross HP
would be a hopefull estimate for such a build.
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VALVE / BORE Ratio
The valve to bore ratio should be:
52-52.5% of the bore for Wedge heads.
53-53.5% for Canted valve, rotated canted valve (Mopar P/S hemi) and true Hemi.
If you decrease intake exhaust ratio down to 70-71% you can move both intake and
exhaust valves over to the exhaust side and increase intake valve size by .5-1%.
Anytime you increase valve size over the above stated Valve/Bore ratio you will see
a small gain in CFM but the discharge coefficient drops and takes your power with it.
An over shrouded valve instills a host of nasty scenario's, the two worst being
decreased discharge coefficient and increased reversion below and above intake
tuned power band.
(according to Darin Morgan)
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I have more faith in the A Engine Rocker Stands over the Magnum style Rocker Pedestals. I am aware that the Magnum RT (cast)heads flow more air than any other OEM head, consequently making the Eddy Aluminum versions a great buy, but I don't think the Eddy's would accept even a 2.080" Intake valve. I'm looking to use a 2.100" for my 422. Indy used to market the 360-1 that would have made a great choice for strokers. Currently though, 360-1 heads aren't offered new and there is more negative publicity surrounding Indy, discouraging me from considering them as a option. I'm also looking to what HughesEngines has to offer.
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you've completely misunderstood me in one of my posts, and now seem to have a preconceived notion on my attitude or tone. I'm not being condescending, argumentative, or commanding.
Have a nice day!
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I followed the link to the Dr. J website. The SBC 220 uses the Brodix head as foundation. The SBM 220 doesn't indicate the same. Who casts the SBM 220 ?
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You can send him a PM here his user name is RyanJ. You can also PM Brian from IMM user name ou812 he can also set you up with what you need including some ARP main studs...
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Last machine shop I worked at I had the pleasure of building a stroked 360 with some oval port indy heads I ported. Forged scat crank, scat I-beam rods (the cheap ones) and KB flat top pistons at zero deck. I did a moderate port job on the heads and I remember peak flow being 327 cfm @.650". I remember that number because I achieved it on my first try and was a bit upset due to the fact that I spent a week on one port of my RPM LA heads with 2.080" intake valve and a 5/16" stem and managed 317 cfm @.700". Guess when you start with a better design, everything comes easier. But I'm getting off topic. That 408 with the indy heads had a hydraulic erson roller cam and those crap indy rocker arms. I was not pleased with the pushrod angularity because the pushrod seat in the lifter is very high on the hydraulic roller lifters. None the less, this engine produced 575 hp @ about 6200 rpm. It would spin to 6500, but the valvetrain would not support it and power dropped off significantly. Intake was a matching indy single plane, also ported by yours truly. Keep in mind, this was 11.5:1 CR. Maybe not the most ideal for a daily driver. I cannot remember the specifications on the cam, but I want to say it was 258, 266 @ .050" with a 108 lsa and .375" lobe lift. I'm sure I'm not absolutely correct on the specifications, but I know I'm in the ball park.
Block was studded on the mains. It really needed a solid roller and some T&D rocker arms. Ah well, I wasn't the one to put the parts list together, I just worked with what I was given, minus the indy pushrods. Threw them in the trash and ordered Smith Bros...