‘73 Road Runner 360 stroker?

[ncrobb]

So while the car is off getting patch panels and some rust taken care I have time to ponder on an engine build. Right now it’s a completely stock 318, two barrel with a 3 speed manual trans. The little 318 runs good and has enough power to get around fine but that’s about it. Again, it’s a ‘73 Road Runner and she has the original 3.55 Sure Grip rear which I intend to keep. I have a freshly rebuilt A833 OD trans that I want to use. My overall goal for the car is to be a driver. Not necessarily an everyday driver but a couple days a week. I want to be able to run at highway speeds and light up the tires for a good exhibition pass. With the 3.09 1st gear and the .71 4th gear I think the OD trans will help cover that with the right engine. I have a 1979 360 that is std bore with a crank that has std main journals and turned .010” on the rod journals. The heads have a lot of wear in some of the valve guides. So I have been toying with a 408 stroker kit with around 9.5 or so CR and Edlebrock RPM heads with an RPM Air Gap intake and a 700-750 cfm vacuum secondary carb (maybe a little fuel efficiency here). If I go this route I’d call Comp Cams or Hughes and get a custom grind to make sure it all worked together. I think a decent working combo could easily put out 400-450hp on pump gas which should be enough to make the big car fun to drive and keep it rolling on the highway. Am I off base here? Would a stock bottom end 360 with higher CR pistons and the top end mentioned above be a better choice for a street car? I don’t anticipate any track or street “competition”. I got that out of my system many years ago. Nothing is set in stone, I guess I’m just thinking it through. Any thoughts on the 408 stroker in a driver?

 

[Challenger340]

We would recommend the 408 Stroker strictly on the size/weight of the B Body.... even for a driver.
The 4" Stroke is very simply the "must have" for a satisfying Torque curve on the street when tasked, and the longer arm also has no problem accepting Cam durations conducive, any of the entry level aluminum Heads are also a must.
While nothing wrong with a well built 360, imo, you won't be happy longer term Vrs what could have been in the bigger car ? (the 408 Stroker)

 

[68Moparmaniac]

If ya got the bucks, stroke it
Nothing wrong with more...

 

[YY1]

Factory 3.55 gears in a 318 RR.

That's kind of cool and probably somewhat rare.

I like where you're going with this.


I have almost the same long range plan except I have an LA roller 9.2:1 318 and 5.9 Magnum heads.

I also have an 833 OD and a 72 3.23 SG axle.

I'm very interested whether the near granny 1st in the OD 833 will be usable with the 3.55 gear.

I currently have a running, driving truck with a 440 and 833 OD. IDK what the rear is but 1st is pretty "short" and there's a LOT of 2-3 (across the gate) shifting.

My 2015 Renegade has a crazy low final (4.33 IIRC) and first is real short on it too, but there are 5 more gears after that.

 

[ncrobb]

@YY1 I was lucky to be able to buy the car from the original owners. The gentleman passed away 8 years ago and parked it 2006. When I went to look at it she told me it was completely stock and that he had changed nothing. I noticed a number of odd options on the car: no stripes, no a/c, no chrome, 15” wheels, the 3.55 SG, 7290 yokes, manual disc brakes, power steering with a cooler etc. She said her husband ordered the car and the plan had been for him and his best friend to build an engine and street race it but work moved them to NC so he just drove it as it was. I suppose that was the reason for the performance upgrades and low profile look. She said he let her pick the colors. It’s white with green interior.

The three speed manual in the car has the same gear ratios as the OD box in 1-2-3 and I don’t do much cross gate shifting now. The little 318 pulls surprisingly well so I’m thinking the 360 in whatever configuration won’t have any problems.

 

[YY1]

This just gets more interesting.

My Satellite is a stripper car with a green int and no molding except the side molding.

I don't think manual disk was an option in 73 for a B body, so that's kinda odd.
Power M/C mount (booster) is a different firewall part than manual (studs pressed into a thick sheet metal brace)

Stripe delete was definitely available, though.

What 15" wheels does it have? IIRC those would be C body rallye style (not sure why they did that, though)
Or steelies with wire hubcaps IIRC.

PS cooler may have been optional.

You got the fender tag?


I love oddly optioned cars like this.

My car came without carpet or even a day/night mirror, but it had AC!

 

[ncrobb]

There is a fender tag but I can’t find a pic and the car is an hour away. The wheels are Rallyes with acorn centers. I actually found two build sheets in it. One under the back seat and one under the driver’s bucket seat but neither matches the VIN. Both cars had the same interior.

 

[YY1]

That build sheet issue is common.

I've seen several 3 speed 73/74 RRs but don't remember any with 3.55 rears.

I had a 73 rallye 318 Challenger that came with 3.23 SG. was auto, though.

I imagine yours is fun to drive.

You're basically adding the O/D and a better 1-2 shift pattern.

 

[ncrobb]

I found a pic of the fender tag on my laptop. I think I have them figured out except the one that looks like “HF6” and the top left one that is “J35” or something like that.

Yes it is covered with Ziebart as is everything else under the hood.

 

[YY1]

HF6 is your "high" grade F6 green interior.

 

[YY1]

J35 might be sport mirrors.

 

[YY1]

Sorry, HF6 is the "upper door panel color", really on this car- where the door is painted.

 

[YY1]

Hmm, manual brakes are coded.

Interesting.

 

[ncrobb]

It has dual chrome door mirrors.

 

[Curiousyellow71]

The od tranny will likely brake if you are making power with a stoker w aluminum heads. We did a little tweeking and put 4th where it's suppose to be on a od 833 but it's been so long ago I don't remember what we did. Turned the shifter linkage on the tranny upside down I believe. 3.55s very unusual I imagine it was pretty peppy w 3.09 granny and 3.55s.
We have a 73 roadrunner red w white stripe 318 car...no such luck on 3.55s. We original built a 360 and with the highway gears it was a slug...so stroker I say

 

[YY1]

I don't see the gear on the fender tag.
I'm not sure what the protocol was if std vs opt axle gear.

Don't see a stripe delete either, but again, not sure if it was std.
Curious if your car has/had RR decals, and of so where (besides the hood header panel).
Would they have been where the stripe has them?

Now that I'm thinking about it, the only non-stripe 73/74 cars I think I've seen have been full vinyl top cars.

 

[ncrobb]

It has a RR decal and emblem about halfway up the B pillars as shown in my avatar. This locates them where they would have been with the stripe.

 

[dvw]

I just finished a 360 Magnum/904 swap in a 68 Satellite convertible. 3.23 gear, low gear set in the 904, 2500 converter, 8.9-1, Eddy 660 carb, heads, and RPM intake, comp [email protected]" hyd roller, 1 5/8" headers. It will blow the tires (275/60x15) off from a roll at low speed. Runs amazingly well on 87 octane. By the seat of the pants easy low/mid 13 second ride.
Doug

 

[PRHeads]

I like the big TQ numbers you get with extra cubes.

If the budget is there...... stroke it.
You’ll never be able to do it as cheaply as you can at this point in the process.