The 493 Cross Ram Lives

[b569rr]

 

[Budnicks]

I looks great too...

congrats

what are your plans & expectations ?

any details on the build you care to share ?

 

[HEMI-ITIS]

Me likey!!

 

[b569rr]

Well here are the details. The car is a non numbers 383 4 speed 3.55 SG car. The MP 284/484 went flat last summer after 10 years and 20K miles. I had this cross ram stroker set up for another project but I lost that car. I had issues at first modding the Road Runner as it has never been cut or welded on, the original floor pans and trunk are like new.

It is a 68 440 block with the 30 over 4.15 stroker kit giving me 493 inches. It is zero decked with a 0.040 MLS gasket for quench height. Rings are perfect circle file fit.

The fuel tank is a stock replacement with an in-tank Walbro pump. It can push 400 lpm with zero head, and is very quiet.

The heads are non cnc'd Indy EZ's as I'm not a serious racer and I will only go the track a couple times a year. My machinist said the valves that came with the head were not of a recognizable brand, so Manley severe duties went in. I did polish out the exhaust and chambers, unshrouded the valves, cleaned up the intake runners and gasket matched all.
Dave Hughes was a big help. I told him I wanted a hydraulic roller for a 12.1 to 1 engine, and a 25% mix of race gas. So I got his cam, lifters, Cryo 1.6 rockers and pushrods. The cam is 108 LSA, 104 centerline, 245 duration at 50, and 587 lift at 50, cam is degree per Hughes designed at 3 degrees advanced. I'm not sure what this means yet.

The ignition is an old Crane HI-6 fireball unit that I have had for years, and a RB fire core distributor with 8.5 mm taylor wires.

I upgraded to a 18 spline 4 speed vs my old 23, and run an 11" housing, hayes flywheel, and centerforce clutch. Brewers was a big help.

The exhaust is all TTI via a member here and Hughes, but I welded it up with turbo v band clamps. 2" primaries into 3.5" collector into a 3" exhaust. The DynaMax super turbo mufflers from TTI are way quieter than the 40 series flow masters on the 383. The RR has 3" Quicktime exhaust cutouts.

For tires, the rear has Mickey Thompson Sportsman 28" x 12 x 15.

This fall I will upgrade to a Dana 60 from strange.

As for me, I've been playing with cars my whole life but nothing serious on power. The Road Runner is my first Mopar. I will play with the tune. I made my own carb synchronizer and got them matched. I installed dual wide band sensors and the sensors are giving me erratic readings. Timing right now is 12 baseline and 35 total all in by 3200. Its too new to see if I need to play with that as all I have done is a few high rpm warm up sessions and 20 miles of ring setting. Time to dump the brad penn break in oil.

My weak point is the cooling. I'm running a stock (newer) 26" 3 core radiator, shroud and a large fan right where it should be. It worked great on the 383. The thermostat is a fail open 180. On cruise is stays at 180. When I was getting on it, it creeped up to 210 but no higher. The housing is from hughes which I got after looking at my 2006 440 source unit with small passages. The water pump is the vaned 440 source unit and I'm not sure how great it works. I'm going to see if I can find a high flow stat and see if that helps.

And carbs are twin 650 thunder series Eddy's right out of the box. I'm a holley guy, but I can learn to play with them. I bought the cross ram and linkage from Mancin about 10 years ago. The car starts up very good when cold. It seems happiest at 1100-1200 idle. If I idle below that, the plugs will load up. They clean up quick with a couple of revs. manifold vacuum is a steady 6" Hg.

This site has been a great help. Did I miss anything?

Tom

 

[Budnicks]

Sounds like a sweet set up...

Thanks for sharing

 

[cdr]

a suggestion, shorten the dist mechanical advance, it needs to run 18 to 24 initial & 33 to 36 total, that will make it run much better & run cooler.


my 512 likes 24 initial 34 total

 

[b569rr]

a suggestion, shorten the dist mechanical advance, it needs to run 18 to 24 initial & 33 to 36 total, that will make it run much better & run cooler.


my 512 likes 24 initial 34 total

Thanks.

 

[64 Post]

Agree with cdr. Also my experience with Eddy carbs (Thunder AVS) is they don't like anything under 9" of vacuum, although bringing in more initial is going to increase your vacuum a bit. I believe their manual gives the 9" figure.

Oh, and watch your fuel pressure with those carbs. 5 psi should do it.

 

[b569rr]

Thanks. I'll take some timing out this weekend and move the initial up.

Where do you think I should have 100% of the mechanical timing in by? After checking it today, it is 3500 rpm with the our of the box (street/strip) springs per Firecore. My old 10.1 383 was in at 2200. I'm no pro at this, but rather than welding my slots to limit the advance mechanically, I'm thinking I could throw some lighter springs in it to get my initial in early at 1100 rpm then total in by 34-36. Anyone do this? My total advance would be in early though and I'm weary of detonation and have been listening avidly. Have not heard any yet under WOT.

Also, my wide band sensors starting giving me descent signals. I may have fouled the O2 sensors on start up. I'm at 12 to 1 at WOT and 14 at idle right out of the box, and I'm at 500 feet above sea level. The regulator is controlling fuel pressure at 5 psig.

Thanks for your input.

Tom

 

[cdr]

the fire core is what i have, it can be set anyway you want, mine is about in the middle of the slots, with the compression you have try 2500 all in , if it rattles go 3000 & so on.

 

[cdr]

no reason to weld the slots.

 

[dvw]

Agree with cdr. Also my experience with Eddy carbs (Thunder AVS) is they don't like anything under 9" of vacuum, although bringing in more initial is going to increase your vacuum a bit. I believe their manual gives the 9" figure.

Oh, and watch your fuel pressure with those carbs. 5 psi should do it.

I've never checked my vacuum but I can tell you that my Eddy 750's idle just fine and have great driveability with a [email protected]" roller. Never had an issue with my 498 w/[email protected]" roller with a crossram either.
Doug

 

[69 GTX]

Good looking car! Should run great. Did you have it dyno'd?

 

[b569rr]

The carbs do respond well. It doesn't bog at all.

Well of course I can't find my springs for the distributor or advance gauges. Looks like the MP ones are not available anymore. I think I have a Mallory kit that looks close. I'll mess with the dizzy this weekend and report back.

There are two dyno shops close to me and a trip is in order. Then it's off to the drags with my trash talking brother and his whippled cobra. The looser details the others car.

 

[drobertson]

Dang I just love it when people build muscle cars that look period correct from the outside but have hidden modifications! Sweet bird! I'd sure love to own it!

 

[b569rr]

First off thanks for your tips. It LOVED the changes.
I had the dizzy out a couple times and decided to stay at 18 initial with 34 total all in by 3000 rpm. The out of the box firecore had 20 degrees of timing in it with heavy springs.

I recalibrated my carb linkage also. I still have out of the box jetting and we are at 14 at idle at 1100 rpm. I'm pulling 9" Hg with no signal to the vacuum port. I will take it out and see how the temp goes. So far with 45 minutes of idling at home, it took forever to get to 180 degrees, where before I could get there in 10 minutes.

And just when I want to take it our for a test, it starts raining. Man this thing sounds good.

Tom

 

[cdr]

set the vacuum so it only ads about 5 deg, ported vacuum

 

[b569rr]

Well I guess it's cool that you make enough power to break things.

I put M/T street ET's on it yesterday. Revved it to 4K and dumped the clutch. It grabbed, shifted at 6300. Slammed it into second and boom.

I knew the 8.75 was my weak point but was in denial that I would hurt it on the street.

Tom

 

[HEMI-ITIS]

I was gunna say those Sportsmans will last forever due to NO HOOK,,,,lol.

 

[SUPERSTOCKRACER]

Agree with cdr. Also my experience with Eddy carbs (Thunder AVS) is they don't like anything under 9" of vacuum, although bringing in more initial is going to increase your vacuum a bit. I believe their manual gives the 9" figure.

Oh, and watch your fuel pressure with those carbs. 5 psi should do it.

Disregard this guys reply. Everything is wrong with it. I run them with less vacuum and with 6.5 psi of fuel pressure and go 8.80's @151.54 mph with them.
And my pump gas wedge indy motor that goes 9.96@136 mph.