• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

68 roadrunner resto-mod/resortation

Not surprised the new hemi build came out substantially higher. There's a lot of intangibles that can be overlooked and really add up.

Decisions are the hard part of this game!
 
If its between the 440 and a 451, See what parts are available more readily available and less expensive. I am guessing you will have more performance piston choices with the 451, Seems leaving a 440 with the stock stroke is uncommon for performance builds. Finding a place that sells a pre balanced crank, rod, piston combo will save some bucks. I know 440 source sells a 451 stroker combo with a 24cc dish piston to choose from for example, but they only sell one 440/440 piston that does not work for us guys that like boost.
If you know your 440 block is good though???

I like your car, seems its coming along well.
How much Hp are you aiming for?
 
I am not certain my block is good but blocks are abundant so I am not worried. I am leaning more towards to 451, it'll get girdles and better mains. I don't really have a goal, with the parts I am collecting the limiting factor will be the main webs not the parts. I would like some serious rwhp but we will see.
 
There's a few of us on here running the 451's and most are getting 500-550 hp with pretty mild builds. So far I really like mine for all that I have in it.
 
I am not sure where I'll be sitting, I am guessing somewhere in that ballpark, at least until it starts making boost.
 
Well with those s366's, you should have no prob making gobs of power. I am curious as to what rpm they will start spooling up. What's the A/R ratio on your 366's? If you make 550hp N/A, you prob will bypass the efficiency zone on those turbs completley, may work out better dropping your N/Ahp. Not speaking from experience though, just looking at the compressor map.
Going to subcribe to your thread, I like the ideas you have about your car.
 
The A/R is .91, I am at work today so I don't have the math with me that I did but I'll post it later and maybe get someone with some knowledge to chime in. I am as rookie as it gets when it comes to boost but I have been reading lots and asking a lot of questions.
 
Last edited:
Pressure Ratio = 14.7 + boost psi / 14.7
PR = 14.7 + 12psi / 14.7
PR = 1.816

L = in³/61.024
L = 451/61.024
L = 7.39L

CFM = Liters x RPM x Volumetric Efficiency x Pressure ratio / 5660
CFM = 7.39 x 6000 x 90 x 1.816
CFM = 1280.38

lb/min = cfm x 0.069 @ 120F ( found on garretts website)
lb/min = 1280.38 x 0.069
lb/min = 88.346

88.346 / 2 = 44.173 Per turbo

View attachment 299415
It would be a little beyond the optimum, it would be into boost fairly quickly but might start choking after 6000rpm. I have three options at this point. Build a 400 and not stroke it, build a 451 and see what happens (paper isn't always right) or sell the borgs and buy something else.
 
I think twin S366 will be great for what your planning. Your numbers suggest your aiming for 800-900hp? A V.E. of 90% is a bit generous for an old school V8, but 45 lb/min per turbo, rounded to about 10hp per lb, 900hp goal. I don't think you will choke out before then. Can always build the 451, just keep the cam on the mild side, say N/A hp at 450 or less, A PR of 2 will get you to 900hp. Can always go with a bigger cam and valvetrain upgrades later.
Funny you say paper is not always right, spent a lot of time learning and crunching numbers to learn that sizing the turbine side is more important, and it's an experience thing.
My build is a .030 over 440, 9.2 CR, with twin S256, 1.22 A/R. On the small side and not typical, but it's a 100% street car, and I am running a very streetable cam. Have not had it on the road very long yet, still in the break in period, mostly de-bugging and tuneing the carb ect, sorting other things out, only had it up to 3lbs boost so far. Weather has been too wet and have not 100% stomped on it yet, but It seems to kick in at about 2200rpm'ish, most definatly fun to drive. If I make it to 8-9 psi of boost and 5500ish rpm with out choking the turbine I'll be more than happy, I am still confident that it will. Wish I had more experience to offer, perhaps in a few more months when rainy season slows down.
 
I give you credit for selecting the car that opened the Mopar Madness for Muscle Cars back in 68. Great choice. Without your time, funds and commitment the RR was on its way to the crusher or a parts car. Good Luck and Keep on Sharing your Efforts
 
I think twin S366 will be great for what your planning. Your numbers suggest your aiming for 800-900hp? A V.E. of 90% is a bit generous for an old school V8, but 45 lb/min per turbo, rounded to about 10hp per lb, 900hp goal. I don't think you will choke out before then. Can always build the 451, just keep the cam on the mild side, say N/A hp at 450 or less, A PR of 2 will get you to 900hp. Can always go with a bigger cam and valvetrain upgrades later.
Funny you say paper is not always right, spent a lot of time learning and crunching numbers to learn that sizing the turbine side is more important, and it's an experience thing.
My build is a .030 over 440, 9.2 CR, with twin S256, 1.22 A/R. On the small side and not typical, but it's a 100% street car, and I am running a very streetable cam. Have not had it on the road very long yet, still in the break in period, mostly de-bugging and tuneing the carb ect, sorting other things out, only had it up to 3lbs boost so far. Weather has been too wet and have not 100% stomped on it yet, but It seems to kick in at about 2200rpm'ish, most definatly fun to drive. If I make it to 8-9 psi of boost and 5500ish rpm with out choking the turbine I'll be more than happy, I am still confident that it will. Wish I had more experience to offer, perhaps in a few more months when rainy season slows down.

Damn Furry I didn't realize yours was that far along! What blowthru are you running and what does the rest of your fuel system look like? Love seeing more people wanting to be in BOOOOOOST!!
 
Thanks guys, Furry do you have any photos of your set up?

Between bouncing ideas off Mike and Hemi, I am slowly wrapping my head around it and coming up with a solid plan.

Furry, is that Vancouver BC or WA? If it's BC, maybe I'll just come look with my own eyes.
 
Hey Zach,

Here's a thread Furry started a while back may have some good info for you in it http://www.forbbodiesonly.com/mopar...ottom-end-questions&p=910306071#post910306071

So many options it's just about making the best possible bang for the buck! So many options, recommendations and ideas it makes my head spin. You already have a nice set of twins and given your math I think they'll make you plenty happy with either the 440, 400 or 451 build!
 
Here is where I am now, took these today,


, rrunderhood.jpgrrunderhood2.jpg

In placing these turbs, I had a few things to consider that I wanted, your prioritys will prob differ,

1- I did not want to cut a hole in the stock hood, If I wanted to cut a hole I probably would have ended up going with a screw type supercharger or a blower.

2- Tired of working around the long tube headers I had before, wanted to be able to change my starter without pulling my engine so I could move the headers out of the way, and to be easily able to pull the headers, downpipes, and turbs out, with everything else still in place. Easier plug changes a bonus.

3- Daily drivable setup.

Dry enough out to get some traction, seems like boost starts building at about 2600'ish, Think I hit 5lbs at about 2900 but hard to look at guages when I'm driving. At this point, not sure If I would change much in turbo placement if I had to do it all over again. The 73/74 roadrunner hood has lots of room, and I made use of a lot of it. Had It so I could remove the valve covers, but after wrapping the headers they are a bit tight to slide off, I just hammered the cover a bit flatter and it went on ok. Prob would change where I put the drivers side BOV though, minor detail though.

Anyway, I will update my thread, so I don't clutter yours up. Yes, In Vancouver BC, No Prob if you wan't to meet up sometime.

- - - Updated - - -

Damn Furry I didn't realize yours was that far along! What blowthru are you running and what does the rest of your fuel system look like? Love seeing more people wanting to be in BOOOOOOST!!

Its a CSU 750, Carb is good under boost and WOT, cruise, off idle, not good at all, had it on and off the car 5 times now, much better, but still not even close to how I would like it, I'll elaborate when I update my thread.

- - - Updated - - -

Did't mean for the last pic to get in there, but that's a 440 source girdle, on the 440 engine I am running now.
 

Attachments

  • rrgirdle.jpg
    rrgirdle.jpg
    90.8 KB · Views: 257
That's surprising about the CSU carb. I'm not as familiar with them as I am C&S and Proform but aren't they are company where everything is supposed to come set up for your application and flow tested? I would send it back
 
Thanks Mike, that was a good link.

Heres the newest progress, passenger quarter is on and mini tubs are welded up.
 

Attachments

  • image.jpg
    image.jpg
    22.1 KB · Views: 174
  • image.jpg
    image.jpg
    22.2 KB · Views: 179
Well I am still making progress, time for it to go onto the hoist for suspension and stiffeners. Going to build my own 4 link, still havent decided what to do with the front. I would like to do a coilover/k member swap from magnum but with our dollar it would be 6k and that simply isn't in the budget.
 

Attachments

  • image.jpg
    image.jpg
    20.8 KB · Views: 138
  • image.jpg
    image.jpg
    21 KB · Views: 144
Well I have slowly been pick away at small things after all the major rust repair was done, been very busy. I have most of my drivetrain sorted out and welded in US car tools goodies. Going to start with the magnum force pieces now. For the rear coilover mounts, the magnum force kit uses the old shock mounts to locate/support the bracket but mine has seen better days. I plan on installing a piece of tubing in the cross members place to instead of replacing it. Also noticed a few stress cracks in behind it that i never noticed before. Now that I have a pile of parts I will update more frequently with progress.

IMG_4139.JPG IMG_4170.JPG IMG_4567.JPG IMG_4645.JPG IMG_4673.JPG IMG_4676.JPG IMG_4737.JPG IMG_4773.JPG IMG_4774.JPG IMG_4775.JPG
 
Auto Transport Service
Back
Top