The Dodge Challenger Message Board

Couple of questions about the 500 stroker 440 based motor i am building.

This car will be mainly on the street, might see that track every once in awhile, going to have a 5spd manual, not sure on the gear ratio yet, hoping you could help me out on that too. It is going to be MPI and might see a supercharger one day.

First will a set of stage 2 ported eddys from Hughes be sufficent for this engine or do i need to go with a stage 3 port?

Second what camshaft do you suggest for this setup, would like it to be a Hughes cam if it can be, i would like that nice idle sound, but it is not important.

Another thing, the Hughes website says you have to use their valve springs with their camshafts is it true or are stock eddy springs sufficient?

The cam and heads need to match. If one is too big for the other efficiency and drivability will suffer. You will have to decide how much power you want. Hughes "guidelines and requirements" page gives you a rough idea.

The rear gear selection depends on the cam and tire size. I also like to factor in highway cruise speed on a car that sees highways more than race tracks.

Valve springs have to be rated just right for the cam. Too strong a spring wastes power and increases wear. Too weak a spring will not follow the lifter fast enough or float the valve. They also need to be able to compress enough to allow for the amount of valve lift you have without binding.

Always use the springs that match the cam no matter who's cam you use.

Good luck!

"Too weak a spring will not follow the lifter fast enough or float the valve. "

Out of interest, what effect will the springs not following the lifter fast enough have? Loss of horsepower, excessive wear and tear, or some other effect?

Hughes Engines wrote:One of the biggest mistakes you can make is thinking any spring is as good as long as it will handle the lift
and isn't broken. For the cam to operate properly, it must have the proper seat tension to keep the valve
from bouncing on the seat and the proper open tension to keep the valves from floating. It should also have
enough extra lift over and above the valve lift to keep it from coil binding or stacking up. The fact that "it will
handle the lift" answers only one question. You must answer all three at least (seat pressure, open
pressure,and maximum lift). Our cams require springs that are usually higher tension on the seat and lower
tension open than so called "factory" or "Chevy" cams.

Obviously if the valve is bouncing on the seat of slapping into the cam lobe then it is going to cause wear. If the vave is bouncing around or not closing at all or the opening/closing point varying then you will loose pressure and power as a result.

This might explain why I didn't gain any top- end when I put the Edelbrock heads on. I left the springs in which came with the heads (couldn't afford a set from Hughes at the time). The standard ones probably aren't making best use of the cam.

Maybe I could swap them out when I change the pistons/ rings.

Apologies to Spitfire for 'jacking your thread.

I need Hughes 1106 springs ($76 set), if I've read their chart correctly.

No problem tim we are all here to help each other.

Dave do you think i will need stage 2 or stage 3 heads to work well with this engine once the supercharger gets put on? They are going to have to be the 88cc version to keep the compression ratio down.

If stage 2 will be enough i was looking at Hughes HEH 4650BL.

If stage 3 is needed then HEH 5561BL but they suggest a 4.56 gear set for this setup, i dont think i need a set that tall.

If you are going to supercharge the engine you need to build it for that really. Low compression pistons etc. Also a cam designed for supercharger use.

Port flow is not that important with supercharged engines because the intake is under pressure. You don't need well ported heads.

So you have to decide what this engine will be doing really. One size does not fit all so to speak. You have to say "I need it to make this amount of power" and you have to decide if it is being supercharged or not unless you want to completely rebuild the whole engine again at that time.

Going the "evolution" route with it will result in an engine that is neither one thing or another and will be a poor performer as a result. Most "show" cars are VERY poor performers. But as long as they look good sitting in a field the owners are happy.

So decide how much power you want first. Then decide how you want to get it. Don't forget that if you stick a 900+hp supercharged engine in there (that is the sort of power you could easily make) the whole car will need a full chassis/roll cage, the trans and drivetrain/axle will need upgrading to suit and don't be suprised if you cannot stop it overheating. It is a lot to take on.

Tim wrote:This might explain why I didn't gain any top- end when I put the Edelbrock heads on.

I doubt it. There are many factors that could be responsable for that. Such as much lower pressure in the cylinders. Due to switching to ally from iron without raising compression to suit. Plus you have too low compression for the cam anyway I think?

BTW I think the HEH 4650BL would be a good street/strip cam with your 500 inch engine. Plenty of power and torque. Stage 2 heads for sure. I will run the numbers into desktop dyno but you have to be talking 600hp I would have thought? That is enough to make driving pretty "interesting". In other words you will be going sideways a lot when not expecting it unless you have a very light foot!

Well Hughes have already written the formula for this engine for you!

http://www.hughesengines.com/lb/505long_block.asp

Just copy what they have done and you can't go wrong. I would use their first (611hp) version if I were you and use a 4:10 rear gear unless your tyres are really tall?

What are the gearratio's of the 5sp tranny?

Assuming you have around 28"tires I would go for a 3.91 if the 5th gear ratio is 1:1 and if it's like say 0.7:1 I would go for a 4.30

Also I think I would be tempted to still go one cam smaller and use a dual plane manifold to sacrifice some top end HP for a nice flat torque curve from low rpms.

Tim wrote:"Too weak a spring will not follow the lifter fast enough or float the valve. "

Out of interest, what effect will the springs not following the lifter fast enough have? Loss of horsepower, excessive wear and tear, or some other effect?

Worst case scenario : Valve float will occur. Power loss may or may not be noticeable, but that's not the big problem. Valves will hammer on the seats, and the shock will transfer to the valve locks. They will fail (think of the valve as a slide hammer!). When the valve has completely punched throught the lock, it will fall in the cylinder.

Don't ask me how I know...


And don't forget to use a rev limiter. It will not prevent every over-revving possibility (such as switching in the wrong gear), but it's cheap insurance compared to the kind of money you are putting in the engine.

Just my Opinions

Insufficient Valve spring pressure or rate per inch, is a surefire way to bounce the valves on the seat.
This can manifest itself with many seemingly weird valvetrain symptoms, not the least of which is to eventually "knock the heads off the valves", even 1 pc. SS good stuff. Get the correct springs for the profile.

Yep, most hughes stuff needs their springs, or rather a rate per inch conduscive for that profile. They grind their stuff with a little faster ramps to whack the valve open and closed quicker "because they can" with the mopar .904 lifter dia.
Best stay away from the stuff asking for 150 # seat pressure though as it don't live great on a street driven year after year type deal. Stay with the grinds requiring around 120 # on the seat.

SS HEMI guys used to play with slightly less than adequate spring pressure, to actually get the lifter to leave the cam at the top @ rpm to cheat more lift and beat the old lift rules(more lift) and make more power, called "ramping" the lifter, don't YOU do it.

I.M.H.O. "ditch the 5 spd idea". You're gonna need both hands on the wheel to keep the thing on the road, LOL, seriously though, trying to powershift a std @ 600 hp just ain't reccomended if you're using the stock 2 bolt main block.
The stock blocks ain't happy much past 600 anyway.

If using the cross bolted mega-block, forget the above.

The crank flex torsionally even on a 4340 (non-twist??)forging ain't great for the stock #4 main cap, even for a split second while the clutch is disengaged, it's enough to start the hammering and it's not "if" but "rather "when" it exits stage bottom.
Do the automatic and maintain the crank load on #5 main(the fulcrum) so #4 don't take a beat'in.

If building for a blower, then do just that ! Pistons, C.Ratio, etc., and wider lobe separation cam, 110 ? 112? and correctly timed events for blower. Give B.D.S. (blower Drive Service, California) a call, they have excellent flat tappet solid profiles available, 4500/4600 series are thumpers, ground by ISKY for B.D.S., they are some of best bar-none !

Blower Pistons; If using EDDY's W/quench side, call J.E. Tech, inquire if they build a "keithcraft" Ford type "concave" reverse dome configuration Piston for a BB Mopar, or if they'd build it ? Thats proven to be a "hitter" on blower deals of late, no reason it shouldn't work on the Mopar as well.

Hope I ain't bummed 'ya out, just my opinions.

Excellent well informed opinion.

Thank you all for the opinons and suggestions, all will be considered and i will make my mind up and let you know. And maybe i mislead you but its only going to be a a little ati procharger not a big ass 8-71 blower, but still big enough to make some power.

You will still be better off with low compression to use with the blower. Otherwise you will suffer from lots of detonation problems and overheating no matter what their salesman tells you. You would be looking at intercoolers and water injection to try and control it.

Also, even with a small procharger and a milder cam, you are looking at making well over 600hp.

I know someone with a 650hp Hemi in an otherwise stock and restored e-body. It is a real handfull. It gets our of shape real easy and the fun soon wears off. On the track it runs about the same as a mild 340 because it cannot get the power to the ground. It has to be driven so carefully that it may as well have had a 318 fitted.

I am not trying to put you off the idea! I am just pointing out that it is not that easy or simple.

Likewise, thanks guys for the feedback on the valve springs. I’ll try and get a correct set from Hughes over the winter, so they can be in the car before it gets used in anger again. I may even go for one of their valve spring installation kits, which includes the valves, retainers, locks and Viton positive seals. That way, if there has been any wear and tear due to the incorrect springs being fitted, I can correct that at the same time.

I’ve got a rev limiter built into the MSD digital ignition. It’s adjusted to about 300rpm above my shift point when racing.

I've been thinking about it and I have decided to ditch the supercharger idea, but the 500 stroker is still on. So would stage 2 heads and the HEH 4650BL still work well with this engine, I was planning on having a perfromer rpm manifold machined for the MPI. Also since the supercharger will be ditched I will get the 84cc version of the eddys to up the compression a bit. 4.10 still ok for the rear?

Go for it!

Looks good !