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68 390 heading for the dyno soon |
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jcisworthy
AMC Addicted Joined: Jul/23/2009 Location: North Carolina Status: Offline Points: 2805 |
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Posted: May/15/2018 at 4:20pm |
Should have this 68 390 on the dyno hopefully Friday. Made a stock appearing deep oil pan using an AMC stock pan and the bottom from a stock SBC oil pan with a Canton internal pickup.
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Specializing in dyno services, engine building, and cylinder head porting
rbjracing.com Phone Number 518-915-3203 |
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6PakBee
Supporter of TheAMCForum Charter Member Joined: Jul/01/2007 Location: North Dakota Status: Offline Points: 5457 |
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Wow, that is nice work on that pan.
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Roger Gazur
1969 'B' Scheme SC/Rambler 1970 RWB 4-spd Machine 1970 Sonic Silver auto AMX All project cars. Forum Cockroach |
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SONOFAMX
AMC Apprentice Joined: Aug/08/2007 Location: Indiana Status: Offline Points: 226 |
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Very nice John
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Did you mean GMC?
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mmaher94087
AMC Addicted Joined: Apr/01/2008 Location: Arizona Status: Offline Points: 1690 |
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Placing the cork on the front of the pan ought to make life easier. Nice welding job!
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Mike
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Ram Air Rick
Supporter of TheAMCForum Joined: Jul/04/2007 Location: United States Status: Offline Points: 2668 |
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What a stealthy cool look on the oil pan !
Nice mill ! Well done ! Please post dyno results when done ! Rich C.
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jcisworthy
AMC Addicted Joined: Jul/23/2009 Location: North Carolina Status: Offline Points: 2805 |
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Little delay of game. After a couple heat cycles one head leaked water.
Doing another set of heads. This is the second head this happened to in the same sopt so I started looking at them along with an untouched casting. I found that this little spot is a thin spot on in the castings. There is a parting line there inside and out. If there was not a parting line inside the water jacked in this spot the thickness would be more than enough. Bringing my bowl cut in .050" less will leave .080 or so thickness there. There is a minimum of .130" all around the hole. Hole is about .100" in diameter. Engine made 444 HP and 452 TQ after cam break in and no tuning on a 5500 rpm pull. I think there was water in the hole at that point. Went to start it again and it was hydro locked. I expected about 50 more ft lbs of TQ and 450-475 hp. For a small cam this engine made very good power and when it is fixed it will make more. Cam is a Bullet custom ground on .904 lobes, 214/226 @ .050, .544/.576 lift with 1.7 rockers, 114 LSA in at 110 9.0 compression, heads flow 250-255 through an Edelbrock R4B intake at the lift of the cam and 275-280 through the heads at the lift. 401 Wiseco 27cc dish pistons and Molnar 5.858" rods. Pistons are .050 out of hole with Felpro .045 compressed gaskets This is the first time I had a ported iron head leak on or off the dyno. Unfortunate but such is life sometimes. |
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Specializing in dyno services, engine building, and cylinder head porting
rbjracing.com Phone Number 518-915-3203 |
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jpnjim
AMC Addicted Joined: Nov/25/2007 Location: New England Status: Offline Points: 2752 |
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Very interesting build John!
Sorry the water port bit you, but you'll never know what the limitations are if you don't push the boundaries. Small cam 9:1 build with an R4b is right up my alley, you might end up with the mildest idling 500/500, 87 octane AMC on the planet! I had a couple questions, why the wide 114lsa? were you trying for smooth idle & low octane capable? I guess the R4b is for it's stout mid range, did you find many places to improve it? If you were able to flow it, how did it look on the bench? edit, I reread your post, looks like the R4b ate 25 cfms of your flow work, not bad for a dual plane designed in the 1960's, did you do anything to the intake besides port match it? Are you running the divider as delivered? (notch cut out between the rear two barrels). My build is similar in some ways both my lobes are similar to your exhaust at 228 @.050" .564 lift (904 grind) but I went with a 108LSA to get the early intake closing/increased cylinder pressure. I'll most likely also use an R4b, for the low end, but also to help tame the overlap/idle quality. What's the application for this engine? Would be great in almost anything (from Trail Jeep to tow vehicle to a Street Strip Rebel Machine). Actually has tire burning Rebel Machine written all over it! Thank you for taking the time to post up real builds with real numbers here! Even the untuned 444/452 is very impressive for a 9:1 build with a 214/226 cam! Nice work.
Edited by jpnjim - May/22/2018 at 2:45pm |
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71 P-code 4spd Javelin/AMX
some Jeeps and some Fords |
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jcisworthy
AMC Addicted Joined: Jul/23/2009 Location: North Carolina Status: Offline Points: 2805 |
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Thanks Jim, this is going in a 68 Ambassador 390 car.
The R4B and air gap hurt these heads 25-30 CFM after .500 or so. Torker hurts them about 15. The intake is the customers so that is why I used. I do like them though and I am not opposed to it for this build. I extended the divider slot and port matched it. When I have a small cam in a decent size CID engine I set the cam up like this. The CID gets the low end and the cam install plus heads get the mid and upper. I went with an LS 1.7 ratio pro comp T&D rocker shaft copy for this engine also. The engine had valve float at 5700 or so but I think it was the geometry. I set it up according to T&D instructions with a supplied tab but I was not excited with the way it engaged the valve, or it was not the way I would have set it up anyway. I think that is what caused the float because I have 360# open pressure on a 8mm stem relatively light valve, 1.270" od PAC racing spring and light retainer. I cant see this engine floating until something north of 7K rpm's. |
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Specializing in dyno services, engine building, and cylinder head porting
rbjracing.com Phone Number 518-915-3203 |
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jcisworthy
AMC Addicted Joined: Jul/23/2009 Location: North Carolina Status: Offline Points: 2805 |
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Dyno pull
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Specializing in dyno services, engine building, and cylinder head porting
rbjracing.com Phone Number 518-915-3203 |
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jpnjim
AMC Addicted Joined: Nov/25/2007 Location: New England Status: Offline Points: 2752 |
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Thanks for the informative response and for putting the dyno sheet up!
Wiseco pistons, Molnar rods, LS valvetrain, nicely worked over dogleg heads and what I'm guessing is a very smooth cam that makes 400+ lb/ft everywhere in an Ambo = sweet sleeper that will surprise a lot of unsuspecting people |
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71 P-code 4spd Javelin/AMX
some Jeeps and some Fords |
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