Moparts

Roadrunner engine swap

Posted By: Paul112554

Roadrunner engine swap - 01/15/14 07:05 AM

Hello Moparts members,

I know I'm gonna get hoots & howls over this one, but I have a 69' 383 Roadrunner that I would like to swap a small block into.

I've owned this car since 1974, buying it from a NY State Police impound auction for $200 with less than 20k on the clock. It hasn't been numbers matching car since the late 70's when I striped & gutted it for the drags. These cars were still and dime a dozen, and I never figured all those years ago that I'd still have it way into the second decade of the 21st century!

I last drove it in 2001, and the body is still viable...considering it has NEVER seen an salted Upstate NY winter road.

That said...I would like to give my Roadrunner one last body make-over by patching a few minor holes, having it painted to match my silver 2012 Challenger, and upgrading the suspension. I would consider a small block crate motor, or if possible, a still running 5.2L from a 92' 4x4 Dakota that's rusting away in the back yard...if that's feasible.

ANY helpful info and/or guidance would be greatly appreciated.
Posted By: Kern Dog

Re: Roadrunner engine swap - 01/15/14 07:09 AM

Its not anyones place to expect you to build the car to their tastes, but why not stick with a big block?
Posted By: Paul112554

Re: Roadrunner engine swap - 01/15/14 07:27 AM

It's a l-o-n-g story of well-intentioned friends, a project started then put on hold, making a car "disappear" because of divorce & family court...blah-blah-blah.

Bottom line is the engine & tranny was removed in '02, sat outside under a tarp, and is now just a fancy door stop.

That, the price of gas, having a car that you can visibly watch the gas gauge move as you drive...I just want to drive the car again.
Posted By: Daty Rogers

Re: Roadrunner engine swap - 01/15/14 07:44 AM

Why not do a stroked SB? That'll give you the power without the weight, cost is about the same.

-Daty
Posted By: buildanother

Re: Roadrunner engine swap - 01/15/14 07:49 AM

Sure, why not a stroker small block, lightened even more with eddy heads, little bit of cam and 10:1 compression that would balance that car out a bit and whoop the baseline 383 all day. It's your car.
Posted By: Polarapete

Re: Roadrunner engine swap - 01/15/14 07:49 AM

All the parts and pieces that you need are common to any small block powered B-body of that era.

I actually parted out a '69 Road Runner that had a 340 4 speed combo in the mid 80's. Then it was a rusty hulk, today the same car would be e-Bay material and commanding a big price...times change.
Posted By: Paul112554

Re: Roadrunner engine swap - 01/15/14 08:18 AM

I'm open to any suggestions concerning a SB swap. But what would it take to get a 5.2L or 5.9L motor in the engine bay? Do I need to replace the K-member, or is there a "kit" for this...and who would make this?
Posted By: Sixgun

Re: Roadrunner engine swap - 01/15/14 08:25 AM

No kit needed.Use all challenger or B body smallblock mounts, headers etc.Readily available.
Posted By: RapidRobert

Re: Roadrunner engine swap - 01/15/14 06:00 PM

I'd suggest a 360 or the 5.9 (360) mag as you mentioned
Posted By: mikemee1331

Re: Roadrunner engine swap - 01/16/14 01:11 AM

i'm not trying to sway you in either direction but 383's are pretty cheap to pick up verses a crate small block. put a 2 barrel carb in it and i'll bet the money saved would more than make up for the gas savings. i'm not a small block guru but i don't think a big block trans will bolt up?

where abouts in Upstate? me and my Road Runner are from Rochester!
Posted By: Paul112554

Re: Roadrunner engine swap - 01/16/14 01:44 AM

Ahhhhh a fellow New Yorker! I'm from the Albany area in what we refer to as the Helderberg Hill Towns.
Posted By: mikemee1331

Re: Roadrunner engine swap - 01/16/14 01:47 AM

Quote:

Ahhhhh a fellow New Yorker! I'm from the Albany area in what we refer to as the Helderberg Hill Towns.

and welcome aboard i might add
Posted By: mopar346

Re: Roadrunner engine swap - 01/16/14 04:39 AM

SB & BB tranny is different. Go BB with a thermoquad, small primaries are capable of gas mileage is geared right and you stay out of it, that's the big IF. The fun is it is there when you want it. The other thing is how much are you really gonna drive it? 5 miles difference which is hopeful will only make a minimal difference useless you are gonna drive 10,000 miles a year. If you want mileage stay away from the modern 5.2/5.9 magnums, I have several Dakotas and had a Durango, only 14 mpg regardless how I drove and a RR is probably as heavy.

10000/15 = 666.6
10000/20 = 500
difference 166.6 gallons X 4.00 (guess on NY gas, mine is 3.20) = 666.4

If you use 10 vs. 15 miles the number doubles, the truth is probably somewhere in the middle AND that is if you drive it 10000 miles a year which is doubtful.

I'd play that to have a BB under the hood.
Posted By: Kern Dog

Re: Roadrunner engine swap - 01/16/14 06:16 AM

Quote:

If you want mileage stay away from the modern 5.2/5.9 magnums, I have several Dakotas and had a Durango, only 14 mpg regardless how I drove and a RR is probably as heavy.




The Durango 4x4 surely weighs more than a 3700 lb Road Runner. A heavy truck/SUV with big tires sucks gas no matter which engine it had.
My vote would be to stay with a 383, but if the OP wants to use a 318/360, you could build a mild 360 with Magnum heads and a Thermoquad, run dual 2 1/4" pipes, a lockup A-999 low gear trans and a 3.23 gear. You would have a relatively peppy car with 18-20 mpg capability.
Posted By: Andrewh

Re: Roadrunner engine swap - 01/16/14 03:24 PM

5.9 or 5.2 swap should be realitivly cheap and quick.

360 mounts from shumakers(sp)

LA 360 oil pan and pick up for a car. (110 new from mopar).

cross wind intake from ebay (200).

new sb distributer or junkyard one with pertronix in it.

a sb 727.

drive shaft

electric fuel pump

electric fan.

and you are done.

bargin hunting would probably get you in right at 1k. not counting a rebuild of the engine or whatever.

good low mileage magnums can still be had.
Posted By: roadrunninMark

Re: Roadrunner engine swap - 01/16/14 04:14 PM

If you want a SB and mileage, I would swap in a gen3 hemi and 46rh trans (if you keep the NAG1, it would be better but even more expensive to get to run). Yes it will be expensive compared to what everyone has mentioned but you can probably get 30MPG fairly easy with the right rear gear. Then when you want more power, add a supercharger and you still can have great mileage with big power.
Posted By: RapidRobert

Re: Roadrunner engine swap - 01/16/14 04:15 PM

for the mag (5.2/5.9) in addition get an LA timing cover, a parts house mech fuel pump and the Hughes engines' cam extension (it's dirt cheap, only 15-20 ish iirc) and an LA water pump. EDIT both the early cast iron & the later alum pumps will fit depending on which side the rad lower nipple is on tho the alum pump is far better and I would definitely weld an anticav plate to the iron one & it's a good idea for the alum one also.
Posted By: mikemee1331

Re: Roadrunner engine swap - 01/16/14 04:33 PM

Quote:

It's a l-o-n-g story of well-intentioned friends, a project started then put on hold, making a car "disappear" because of divorce & family court...blah-blah-blah.

Bottom line is the engine & tranny was removed in '02, sat outside under a tarp, and is now just a fancy door stop.

That, the price of gas, having a car that you can visibly watch the gas gauge move as you drive...I just want to drive the car again.

if that engine isn't seized why not just do a cheapo rebuild, possibly change out the cam for a non-hipo one, put 2 barrel on it, get a lower stall converter, lower the rear gear ratio and call it done? if the objective is to get the car on the road again and get better mileage that's what i'd do. given the weight of the car it's only gonna get so good. the other option is to find a parts car that is already a small block and just swap out the parts?
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