The Dodge Challenger Message Board

Hey fellas. Whats your thoughts on this build I was considering. A daily driver capable of pushing out 400hp and hopefully tapping ino the 12's with 91 octane being the best fuel available.

1968 340 casting
Displaced to 416 CID via a .030 over bore combined with a Hughes Engines crank kit (416-KStreet-30)
9.5:1 compression
Hughes hydraulic cam either
HEH 3742AL or HEH 4246AL
Hughes Stage II ported iron heads with 2.055/1.625
1.6 ratio rockers
MP M1 or Edelbrock Air-Gap intake
(Not sure on the carb)
Topped of with a 318 air cleaner pie pan =)
TTI headers
(Not sure on the stall)
reverse valve pattern 727 trans w/a gunslinger pistol grip
backed by a '489 with a 3.91 locker or posi unit.

Any and all suggestions very much welcomed. Cheers!

I personally would not go higher than the 3742 cam on a true street small block car.

If you intend to use it on the street rarely and really need the stronger cam and have the quality machine work/lighter rods and pistons so you can rev to 7000rpm OK then go for the bigger cam.

Same with the heads. With the smaller cam Stage one if you see a lot of street cruising and stage two if strip times are more important. But stage two for sure if you use the bigger cam.

You are going to need a 10 inch converter for either cam I think?

Consider using 4.10:1 gears for the best ET with either cam.

OK, my turn

1968 340 casting
Displaced to 416 CID
9.5:1 compression I would go for 10:1 with a .38 compressed gasket
Hughes hydraulic cam either Go for a solid cam
HEH 3742AL or HEH 4246AL HTL 5256AS --> 252/256* 572/579" with 1.5
Hughes Stage II ported iron heads with 2.055/1.625 Edelbrocks are better for about same price level
1.6 ratio rockers For streetuse 1.5's gives less stress
MP M1 or Edelbrock Air-Gap intake M1 intake for the above cam
(Not sure on the carb) Speed Demon 750, at least no eddy 750 which won't supply enough fuel
Topped of with a 318 air cleaner pie pan =) Nice...
TTI headers
(Not sure on the stall) 10" about 3000rpm stall
reverse valve pattern 727 trans w/a gunslinger pistol grip
backed by a '489 with a 3.91 locker or posi unit. 4.30's w/ 28" dragradials

*Edelbrock performer rpm heads are top of the line when compared with out-of-the-box heads, and what I see hughes stage2 pricing (999$ with a core supllied) are just slightly cheaper then eddy's.
*By using 10:1 CR with a .38 gasket you have a little bit left tp play around with thinner/thicker gaskets to adjust the CR if needed.
*Solid has a way faster rev and gives more top end power also and as you stated to already change rockers it won't costs much more.
*Concerning camspecs a stroker will take much more cam then a regular 340. The hydraulic mentioned has the same dur. as my previous cam and ran/idled fine in a 340cid already.
*Using 1.6 rockers will give less ideal line-up of the valvetrain which stresses the parts more.
*The M1 has a better topend and with a 10" converter you won't need the trq below 2000rpm anyway, certainly not with 3.91 or 4.30's.
*Had a eddy myself and after a stoplight run it didn't have enough fuel left for the next stoplight take off. Demon solved the problem for me.
*4.30's with 28" tires makes you turn about 3400rpm@60mph Just take your time.
*Dragradial's are a must or else 1st gear and partial 2nd are useless on the street. Mine keep spinning around till 5000rpm in 2nd with streetradials.

This is what I would do if I think about it for a 1/4hour. Quite some changes but hope some of it makes you think and or sens. Just my .02[/b]

After looking at building a stroker, I ended up buying the 402/435 crate motor. It’s a 360 with a 4-inch stroke. I had the heads ported & polished, used an Edlebrock avs 800cfm carb, TTI Exhaust. Have a 2400 stall with a 727. Should be about the same HP as you were looking for. With this set up, the car is what I call barley civilized.

It growls, and lurches at all stop signs, gets 10 miles per gallon with super, and is one twitch away from causing a large laundry bill

If this were my daily driver, I would tone it down just a bit. Maybe a crate 360 with 300 hp would work better?

The setup you mentioned is pretty damn hot for daily driver, but for a weekend bowtie killer, you are right on the money!

The Edelbrock AVS now has a duel feed fuel line, much like the Holley, and should take up to 500hp @ the crank.

I tried the Detroit Locker and scared the out of myself nailing it out of a corner. The Auburn Style posi is a smoother take up for the street, but more maintenance for the strip. You may want to look at sub-frame connectors, as the little beastie will twist a bit..

I ended up with @ 742 Aluminum carrier with 3.55’s. The 3.91 launched like crazy but the fuel bill was amazing! In a perfect world, I would switch gears depending on if it was cruise night or race night!

Just my .02 Have fun!

All good advice.

I will add just a couple of things here.

Iron heads are better than Alloy in every area except ease of porting and weight.

Run 10:1 with alloy heads on that fuel you have but stick to 9:1 or slightly more with iron.

Hans. Your carb was not the problem. It was fuel supply. Think about it. But I agree it would help if you could use higher pressures or a dual feed on the Edelbrock.

"Iron heads are better in every way" ?
- alu heads can handle a higher CR
- much less weight to carry around
- better flow in stock condition
- ease of porting/polishing
- more expensive

Out of the reply's we can see it all depends on the prefered application for your car. Insurenceguy mentioned the most streetfriendly combo with the crate 360 while I suggested the most stripfriendly combo. Dave sits between. So think about how you want to idle / run / use your car and then make the decide how & what. For me the car is for every now-and-then use when the weather is nice etc. and go out to race and make fun of bowties and so on.

My carb had more problems then a bad supply Dave. It just didn't work anymore with the new combo, whichever we did tune it. The Demon works great! That eddy I had had still the single line feed.

72 Challenger (Hans) wrote:"Iron heads are better in every way" ?
- alu heads can handle a higher CR
- much less weight to carry around
- better flow in stock condition
- ease of porting/polishing
- more expensive

You are wrong about them being able to 'handle' a higher compression. The truth is you NEED the higher compression for them to work as well as iron heads. This is because they cool the combustion charge too much and less heat means less cylinder pressure. So you have to increase the compression ratio by about one point to make up for that.

I have three holleys on my engine Hans (holley types have bigger fuel bowls than Edelbrocks - so more reserve) and they have one feed from the regulator. They run out of fuel too! But hopefully I will be fixing that very soon.

Don't blame me on the "handle" part Dave, I'm no freakin' englishman you know but I have to admitt I never looked at it that way. Learned something again today.

The bigger fuel bowls propably gave you enough reserve to refill the bowls after a short 'full throttle' moment. Hmmm, makes me curious about next winter when I plan the Hemi route. My buddy has laying around a tunnelram with twin 1050cfm dominators on top which I may use... Will scare the shit out of me the first time I hit throttle combined with the 4-spd conversion I guess!

By the way, all of the proposed combo's except for the 300hp 360 crate will bring 12's on the strip definetly!

Thanks for all the input fellas. I agree with all of your advice in one way or another. I'm most likely gonna go for the in between route kind of leaning on the hot side. She'll be a daily drive indeed but nothing more than 15 minutes away, so I could cope with the grunt and gulp. I wouldn't mind making a bowtie wince once or two on the weekend. Maybe I should invest on some dog dish wheels?

I'm going the stroker route for sure, so the crate engine combo is most likely out of my pocket range.

Dave will the stage II's be noticeably less comfortable for cruising than the stage I's?

Hans the only reason I picked the iron heads (other than the price) was so that I could run the lower 9.5:1 compression due to 91 octane being the best fuel available? Possibly go up to 10.1:1 with out detonation? Dave your suggestion on that one?

Also I'm I going the right route with the hughes stroker kit? They seemed pretty right on for the price and quality, at least more so than Mancini.

Oh yeah 12 second blasts on the quarter would be a nice consellation as well!

You will get more efficiency at lower rpms with smaller runners. That means more bottom end grunt, less detonation, more mpg etc etc.

The stage twos will be better at higher rpms. Your call.

It is cylinder pressure that dictates when you get detonation. You get lower pressure with alloy because of less heat so you HAVE to go higher compression ratio to get the same pressure and the same power.

I think there was an explanation of this on the Hughes site. Too late for me today to explain. The wife is nagging....

Thanks Dave, I just finished reading the article on the Hughes website. Cleared that misconception up right quick. I'm most likely gonna stick with the iron heads. Is it safe to assume that the head work done by Hughes is very professional? I mean to say that I've seen cheaper ones from Aerohead, but it seems you get a lot more done from Hughes for the price.

Does anyone have heads/headwork done from Hughes that could comment on the quality of their work?

Likewise from Aerohead head's any negative/positive feedback? Just curious...

I am happy with my Hughes heads.

Thanks Dave, I'm sold.

Called the machine shop where I took the 340 to get magnafluxed and cleaned.. ..turns out #2 cylinder has a crack in it - NOT GOOD!

What to do, what to do...hmm might have to go with one of the MP 360 short blocks, @ $1200 seems fairly reasonably priced within my budget compared to the stroker I was cooking up.

We'll see what happens, thanks for all the great info fellas.

Check this out..

Stroker 406 Short Block Assembly
A new addition to the mopar Performance Parts family of short block engines, this Stroker "A" Carb 406 Short Block has all the power and reliability you can use. Features include high-performance connecting rods, cast crankshaft and pistons, and a remanufactured 360 "A" engine block. This short block does not come with camshaft, timing gear or timing set.
5007841 Stroker "A"Carb 406 Short Block

I found it @ http://www.mopartsracing.com/parts/blocks.html

Sweet!

Thank you very much, thats one lead I'll definetly check out. Appreciate it muchos!

Well today I picked up the 340 from the machine shop, it looks a hell of a lot nicer minus the surface rust and old paint. I talked with the gentleman there and he said that the block is still salvagable, by boring it out and sleeving the cyinders...has anyone had this done before? If so does this limit performance potential?

Another point to ponder: I've already spent $350 for the block and machine work. With the costs of the machine work most likely rising if I go this route, perhaps it would be more cost effective to purchase one those MP 360 shortblocks, or even that 406 shortblock Insuranceguy recommended?

In short, continue the build or sell? I'd like to keep within $2000 for the shortblock. What would ya'll do?

Appreciate your thoughts on this fellas.

On another curious note, I called Summit Racing to price them on that MP 406 stroker shortblock #5007841 that Insuranceguy recommended, and the gentleman said that their not available yet. He mentioned that MP might not have made them yet and could just be "testing the waters" to see if there is any interest/demand for them.

I find that kinda hard to believe since there is already a part number assigned to it...any suggestions? Should I try Mancini or somewhere else like that?

Try http://www.mopartsracing.com/ if it is available, they will have it. I bought my crate motor there, and had excellent service. They also might be able to recommend another option. Ask for Lawrence, he's a complete mopar guru. 770-533-9771

As far as staying in budget, I'm the wrong person to ask I would recommend saving to buy what you want, rather than settling. The down side to this theory is it took me several years, and I still could not afford to do what I did, but I did it anyway

Good luck!

Todd

PS here is a few other options!

SHORT BLOCKS 360 MAGNUM/NON MAGNUM
Mopar Performance now offers complete short block assembles for both Magnum and pre- Magnum 360 engines. blocks are bored .020 over, new engine bearings, new pistons, w/.509 hyd. Cam double roller timing chain and cover. Does not include lifters.
4876907 360 pre magnum 8.5 to 1 compression 1,245.00
4876908 360 pre magnum 9.5 to 1 compression 1,245.00
4876906 360 magnum 9.5 to 1 compression 1,449.00
4876913 360 magnum 10.5 to 1 compression 1,449.00
the above 360 engines are balanced as pre-
magnum (1971-91) engines. Not 93 up magnum

Appreciate it Todd, will give them a call first thing in the morning.