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What RPM is best?  
CannTankerous
New User | Posts: 48 | Joined: 06/07
Posted: 10/12/08
10:03 PM

You're welcome. Let's see. Edelbrock heads are a good deal. I like the LA style as it retains the advantage of the strong and stable shaft mounted rockers. If you look at the intake flow specs, Ed. claims 249 cfm @ .500" lift and 251 @ .600" The as-cast port flow "stalls" at this point where the head will not flow more no matter how far you might open the valve. So, the Engle will have plenty of valve action to get most of what you can out of these heads unless you want to get into porting them. Both of these components will pull strong to 6500 as will your RPM intake. An M-1 or Victor single plane intake would not be bad on this engine and would buy you a little more high rpm hp while trading away torque through most of the rpm range. The Perf. rpm is enough though, and the motor will be happier with a 3000 stall running the dual plane than it would be with a big single-plane. The 3500 is ok to cruise with some with a really good cooler, the 3000 will generate less heat though. 10.5 is fine for this build-just make sure it is a true measured figure. Lots of guys think "I've got 10-1 pistons" but really have nowhere near that compression. Witness the restored 440 R/T B or E bods that can barely break 90 in the quarter-it's because of stuff like that. Attention to detail is everything. The 8 3/4 rear is plenty strong for you-and handy to change ratios with a spare 3rd member if you want. The taller tire will give you a longer contact patch. Figure out your horsepower and weight to estimate trap speed. Figure out where your hp peak will occur, and gear the car to through the traps 300-500 rpm higher if you are serious.  


 
CannTankerous
New User | Posts: 48 | Joined: 06/07
Posted: 10/12/08
10:19 PM

Mostly the power brake booster. If you pull much less than 13 or 14" of vacuum they get pretty soft at an idle. You can run a vacuum canister that stores vac. during the time the engine is pulling more vac. at a higher rpm with a one way valve that supplements the booster when you brake. I say lose the power brakes, the vac. prob., the weight and clean up the firewall at the same time. Lose the power steering if you've got it too-there goes another 30 lbs. right off the nose where it counts most, throw the battery in the trunk, get a glass hood with a 6-pack or T/A style scoop and seal it to the carb. Light wheels and tires are suprisingly effective because it removes rotating rather than static weight. Underdrive the alternator and water pump-etc. Oh, most sm. blk. headers are 1 5/8" A bit small for your ride. The 1-3/4" x 34" Hookers would be better, and a min. 2-1/2" mandrel bent exhaust with good mufflers for cruising-3" would not hurt you a bit-I would go 3".  


 
lemming303 lemming303
User | Posts: 50 | Joined: 09/08
Posted: 10/13/08
07:38 AM

Oh yeah I'm definitely goin to upgrade the entire exhaust system, I just didn't put that here. Those stock exhaust manifolds are too small for my liking.
How much difference is non-power brakes? I don't think I've driven a car without them. The same with power steering. The hood on the car now is the rallye type: it has the two small scoops like the new challenger does. I like that style, how much difference will the T/A scoop make? I was planning on buying a glass hood anyway so I may go with that scoop. As far as piston and compression, that number goes off of stroke and head chamber right? I'll make sure it is a higher compression before I buy the pistons. I plan on buying the pistons after I mic the bore in the block now so I can get the right diameter and then when I get the block done I will give them the pistons and everything so that they can mic the pistons to do the bore the correct size. I'll make sure I have the proper compression.
I don't really plan on porting the heads. I believe it will run just fine without it. I may do that in the future, but not any time soon.
Drmopar, thanks for the tire suggestions. I looked last night after I posted that about tires at the mickey thompsons. Those look like pretty good tires, I'll look later at the M&Hs that you talked about.
Thanks everyone for the help, I'm really starting to understand this all better.  


'73 Dodge Challenger Rallye, 340 (Just found, first project)

 
CannTankerous
New User | Posts: 48 | Joined: 06/07
Posted: 10/13/08
11:24 AM

Hey L, A quick note. With that cam you are going to have a torque bomb. Go with a fairly tight 10" converter-3000 stall is plenty for your combo. Always buy quality in a converter-not a place to skimp. Dynamic and many others have what you need. I think you will find peak power at, or just under 6000 rpm with this cam in an engine of this size. Shift it 3-500 higher-maybe 6100-6400 range-run test loops after developing a good repeatable launch technique start at about 6000 raising the shift speed 100 rpm at a time until you get your best repeatable times. I agree with DRM you could get 520-540 hp out of this. You are going to be fast enough to need a cage, so plan on it from the outset. You can more than offset the weight gain of the cage, frame connectors, and easily have a race weight with you in it of 3400-3500 lbs. Of course you can go lighter-depends on how far you want to go. You ought to be looking at low-mid 120s for trap speed. With an all-out chassis this could put you in the high tens, or at least very low 11's even if you don't really optimize everything for the drags. With a tall 29" or so tire you will be looking good with 4.56 gears. You could go up a step or two on the cam-no problem, but with the cam you like you should be able to run your power brakes if you want to keep them. When you look at the cam catalogs the rec. duration @ .050" for a 360 would need to go up about 10 degrees to keep the same rpm range in a 416. The manual brakes really just take a bit of weight and clutter out of the nose or eliminate the prob. of a cam not pulling enough vac. to work them properly at low rpm. You should have enough vac. with 281 deg. duration and 416 cubes. The stock hood looks great, but the scoop is worth a bit from the cooler air and a bit of ram effect on the top end. The 6-pack and T/A were great designs-with science before style. Raising the inlet puts it above the "boundary layer" of dead air that exists in the first inch or so above the body surface and they have sufficient opening area. You pick up about 1% power for every 10 degrees you drop the inlet temperature due to the increased air density. So, going from say 150 to 80 degrees is worthwhile free power. Insulate the fuel line and run a spacer too. Those Wilson 1" tapered spacers are good stuff. Run a "cool can" if you want to mess with it. You simply spiral the fuel line through a can you can pack with ice. Gotta run-we'll talk compression later unless someone beats me to it. L8R  


 
CannTankerous
New User | Posts: 48 | Joined: 06/07
Posted: 10/13/08
11:25 AM

A quick note-geez.  


 
lemming303 lemming303
User | Posts: 50 | Joined: 09/08
Posted: 10/13/08
03:31 PM

I was actually thinking about taking as much weight off as I can. I saw where you can cut out the inside of the doors and things like that to save weight. I think I'm gonna go without power brakes and steering. Like I said though, I've never driven a car without them. Are the brakes real hard like in a car that has power brakes but isnt running? Same with the steering?
Another thing, everyone keeps talking about where I should shift. If its an automatic trans, how do you change that?  I know the newer vehicles run off of tables in the ECM, but how does an old school trans know? Do you change the oil thickness or something?
About the cage, is that a requirement? I don't mind putting one in, I just haven't out much thought into it.  


'73 Dodge Challenger Rallye, 340 (Just found, first project)

 
lemming303 lemming303
User | Posts: 50 | Joined: 09/08
Posted: 10/13/08
03:33 PM

Oh, and my engine is a 340, not 360  


'73 Dodge Challenger Rallye, 340 (Just found, first project)

 
CannTankerous
New User | Posts: 48 | Joined: 06/07
Posted: 10/13/08
06:56 PM

No, the brakes and steering are not like a power assist car with the engine off. Not as light as with power, but not bad at all. Firm Feel has rebuilt manual boxes and the coupler to convert from p/s. Flaming River has a new box which while strong is heavier. You can get 16-1, 20-1, and 24-1 ratios. The 24 was stock in man. equipped cars. It's easier to turn, but 5 1/2 turns lock to lock. The fast 16-1 box can be very heavy with a heavy car and wide tires-not so much with skinnies and lots of alum. and glass up front. The 20-1 would be a nice compromise. MP has an al. master cylinder to drop a few pounds. The shift point is controlled by a governor in the tailshaft. The weights are changed to alter the shift points-A&A Transmissions has a wide selection of these. You might look at a manual valve body also-shifts when you tell it. I would get a repro shop manual from Faxon to check all this (governors-anything stock) stuff out. The cage will be a requirement at the drags. Once they see how fast you run they will kick you out and tell you not to come back w/o one. Get an NHRA rulebook, or you can join NHRA and you get a year of their weekly house organ National Dragster along with your rulebook. ND is very cool for all the ads and classifieds. Start roaming the sites of all the advertisers and see what's out there. I just didn't want to see you do a full interior resto before you found out you needed a cage. Have you done any drag racing before?  


 
lemming303 lemming303
User | Posts: 50 | Joined: 09/08
Posted: 10/13/08
07:49 PM

No, but I have an acquaintance who runs a 55 chevy, but I don't see him much anymore. It was a 1/8 mi car though. I also have a supervisor who is working on a 63 Dart, but he hasn't done much to it. He has been working on some other stuff, like putting a 425 cat motor in a ford f700. His is gonna be way faster than mine though, he's putting a twin turbo 440 in it; supposed to have 1200 hp.
5 1/2 turns is crazy! I think it would get on my nerves trying to use that. How many turns are the other two boxes?
I guess I'm gonna have to alot of reading about transmissions too! I'm a long ways off from that part of the project though. I might get to pick up the car tomorrow. I hope so. Can't wait to start on it!  


'73 Dodge Challenger Rallye, 340 (Just found, first project)

 
CannTankerous
New User | Posts: 48 | Joined: 06/07
Posted: 10/13/08
11:01 PM

Just thinking...while you work on this it would be a good idea to start running something else to get some seat time. Not that you could not hop right in and start running hard, but it sure wouldn't hurt to get a few rounds in a milder car under your belt. Maybe even running the Challenger a bit before you tear it down? My '69 GTX had the 24-1 box-yeah felt like you were calling down orders to the steering room of the Queen Mary! The 20-1 is about 4-1/2, the 16-1 about 3-1/2 like the p/s boxes (15.7-1). You want to run as much caster as you can for high speed stability, which increases steering effort. Still, the 16-1 would be fine if you want. Pick up the mopar performance chassis and engine books for a bit of reading. Not always the latest aftermarket set-ups in there-but a good information foundation to build on. Yes, 340, not 360-forgot for a sec. The larger bore is good not only for the 8 cubes, but larger bores move the cylinder wall away from the outside of the open valves. As you go down far enough in bore size you run into "valve shrouding" not that the 360 is a prob.-just for theory. But in a 318 or 273 say, the outside edge of the opening valve is close enough to the cylinder wall to limit the flow around that portion of the valve. Guys will grind a 45 deg. chamfer above the top ring travel (of course) and clearance the bore out to match the comb. chamber-which may also be ground for more clearance around the valves. If you went to big valve heads later...Bigger bores are better except for flame-front propogation.  


 
lemming303 lemming303
User | Posts: 50 | Joined: 09/08
Posted: 10/14/08
08:04 AM

Like I said before I plan on getting the car running first, and then saving the money to stroke the engine, so I should be able to run it like that. Its gonna take a while to save the couple thousand dollars to stroke the engine. I'm gonna concentrate on getting the car running first. All of the body work and painting will be the last thing I do since I might have to modify areas for the upgrades.
You kind of confused me, is the 360 better than the 340? The 340 strokes to 416 and the 360 strokes to 408 right?  


'73 Dodge Challenger Rallye, 340 (Just found, first project)

 
CannTankerous
New User | Posts: 48 | Joined: 06/07
Posted: 10/14/08
12:06 PM

Sorry, no-I was saying the larger bore of the 340 was a plus. Eight cubes and a bit more room around the valves. Are you planning on the cast 4.00" crank? It would be fine in your horsepower range and RPM. But if you might possibly plan on upping the cam/heads/intake etc. or using nitrous or any kind of forced induction in the future, I'd pony up for the forged stuff. You are right on the 360/408 and 340/416.  


 
lemming303 lemming303
User | Posts: 50 | Joined: 09/08
Posted: 10/14/08
05:03 PM

Yeah I'm going with the forged, probably the Scat. I haven't fully decided yet though. What brand bearings should I use?  


'73 Dodge Challenger Rallye, 340 (Just found, first project)

 
CannTankerous
New User | Posts: 48 | Joined: 06/07
Posted: 10/14/08
10:01 PM

Full-groove chamfered Clevite tri-metals @ .002-.003" are good. The chamfer is for the aftermarket cranks fillet at the journal edge which is much stronger than the factories undercut design.  


 
lemming303 lemming303
User | Posts: 50 | Joined: 09/08
Posted: 10/15/08
09:31 AM

Cool. Thanks for the info, I'll be writing more posts as I start working on this thing.  


'73 Dodge Challenger Rallye, 340 (Just found, first project)

 
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