Factory Appearing (F.A.S.T) Restomod Questions

[TorRed]

Hi All,

I'm strongly considering a 'mostly' stock appearing rebuild of my 1970 Roadrunner (383, 727 Auto, 8.75 Rear) and have some questions for any of you that have taken that path. I already have a G/V overdrive. tight FTI 3000 stall converter for the trans and 4.10 gears for the rear. Not sure about the converter but pretty sure I'll go to a higher gear like 3.91, 3.73 or even 3.55 depending on where the engine's rpm range ends up. As for the motor I'm looking at either the 432 or 489 stroker kits from 440Source but not sure the larger kit will work with stock intake and exhaust? I'll go with either the TTI 2.5" or 3.0" manifold back H pipe exhaust but want to swap the Turbo mufflers for Dynomax UltraFlows. I have the original intake but have a larger 70/71 440 AVS 750cfm carb I'd like to use but again don't know if that's enough carb for the 489 c.i. stroker? I also have a Lunati hydraulic roller I'd like to use but once again it was bought for a higher HP build so don't know if I'm going to have to go milder? I know the 489 will tame it to a large degree so that has me leaning to the 489 for that and for the extra HP it would bring. I would greatly appreciate any and all opinions but especially those who've gone down this path before and have advice on pitfalls, what worked, etc. I've read some really good articles about these types of builds but would really value the opinions / experience of the forum.

Thanks in advance,
Jim

 

[R413]

When cruising down the freeway the engine RPM needs to be higher than the stall speed of the converter. Or you will be slipping and building heat and have no fuel mileage. So plan your gear ratio around this.

 

[TorRed]

When cruising down the freeway the engine RPM needs to be higher than the stall speed of the converter. Or you will be slipping and building heat and have no fuel mileage. So plan your gear ratio around this.

Generally, I agree. However, I have read that at highway speeds with an overdrive it takes much less HP to stay at a given speed that effectively the 'stall' of the converter especially a tight one will drop and not slip at lower rpms. How much it drops is hard to say but somewhere I read 500 rpm is not unusual. Again, would love to get folks actual experiences with this.

Thanks,
Jim

 

[PRHeads]

The stock intake is a huge impediment for making real power……..especially when coupled with exhaust manifolds.

A pump gas, truly street friendly HR cammed combo will be very lucky to get close to 500hp.
Especially if it’s cammed properly for the low cruise rpm that would accompany tallish gears and an OD unit.
Probably end up closer to 450hp.

To put it in perspective……
Low deck 511, ported 906’s(280cfm), 12:1cr, .630 lift solid roller, reworked 301 manifold, Ede 800AVS, HP ex manifolds…….525hp on the dyno.
11.58@117 @3670lbs in a 69 Bee on bias plies.

 

[TorRed]

The stock intake is a huge impediment for making real power……..especially when coupled with exhaust manifolds.

A pump gas, truly street friendly HR cammed combo will be very lucky to get close to 500hp.
Especially if it’s cammed properly for the low cruise rpm that would accompany tallish gears and an OD unit.
Probably end up closer to 450hp.

To put it in perspective……
Low deck 511, ported 906’s(280cfm), 12:1cr, .630 lift solid roller, reworked 301 manifold, Ede 800AVS, HP ex manifolds…….525hp on the dyno.
11.58@117 @3670lbs in a 69 Bee on bias plies.

That's great info, thanks!

 

[Cudadude2]

I’m on that path now. I did a 499” build. Factory intake and exhaust manifolds. On a redline tire earlier this month it went 11.03 @ 124.66 in a 3550 lb 1968 Road Runner.

 

[Cudadude2]

Another car there with a pump gas hydraulic roller build went 12.03 @ 113 on just its second outing letting trans shift itself.

 

[Cudadude2]

A third more sorted build, 499” pump gas solid roller went 11.5 at 117

 

[Curiousyellow71]

I’m on that path now. I did a 499” build. Factory intake and exhaust manifolds. On a redline tire earlier this month it went 11.03 @ 124.66 in a 3550 lb 1968 Road Runner.

View attachment 1758781

I enjoy reading your stock appearing drag racer posts on fb. The elusive 10's are so close!!!!
I wish we were closer to a F.a.s.t. event. Every event is a long trip. We built a 72 satellite. It could be in the spirit of a road runner if we changed grills, we have two hoods..one w fuctioning air grabber, one for a stock satellite. We are running a 542 b engine, it has iron heads that flowed about 325cfm on our bench. Being a 72 it was born with a thermoquad. We are running a 1000cfm version and are experimenting with the cam and compression. Not sure how our 72 spread bore intake compares to the 69..but mopar cast-iron sure stinks to port!
We are repainting the car..so it's not pretty yet.. it has working AC yet, which will slow it down. But that currently does give it more wolf in sheep clothing affect. Hopefully track time next year. Here is our car w the 542.

 

[70ChargerRT]

I just like to read all that BS trolling that everyone does on their FB page and some of the clueless people commenting that don’t even know these are just, like the FB page says, stock appearing, is even funnier. They don’t have a clue the amount of time and money spent to get these cars where they are at and then the crying about the Hemis and 427 cars. Especially the Vettes and Camaros just flat out smoking everybody lol.

 

[Cudadude2]

The Thermoquad intakes are marginally better than the earlier units. That said, still not good.

 

[Curiousyellow71]

The Thermoquad intakes are marginally better than the earlier units. That said, still not good.

I have one completely cut in half.Lol

 

[RemCharger]

The Thermoquad intakes are marginally better than the earlier units. That said, still not good.

I have one completely cut in half.Lol

Little bit more plenum? From my understanding

 

[Curiousyellow71]

Little bit more plenum? From my understanding

I think so..but still has the funky angles where they feed two cylinders from one intake port and the air has to turn more then 90 degrees on some cylinders. It's a lot of work to correct that and make it still look stock. I have never tried to flow a intake bolted to a head to see how they flow. We have direct Connection stage IV heads and the port window is about halfway in size between a maxwedge and stock port. Our intake is deep ported to match. I have two intakes I am playing with. Its extra work to get our fixture to hold up a head with a iron intake bolted on.
Performance changes will have to be measured in e.t. Lol
We could get more flow out of ours heads..but guessing that is a waste of time till we solve the intake. The 72 intakes aren't that easy to find to cut on.
My brother and I are just going to have fun with this car regardless of the outcome, race against our own times. But its always fun to compete.

 

[ckessel]

Back in the 80's I had the exhaust on my Duster Alumacoated, which is a plasma spray. Makes me wonder if you could do opposite to a set of Stealth heads. Iron plasma spray onto the aluminum. Would help make a magnet stick.

 

[Curiousyellow71]

Back in the 80's I had the exhaust on my Duster Alumacoated, which is a plasma spray. Makes me wonder if you could do opposite to a set of Stealth heads. Iron plasma spray onto the aluminum. Would help make a magnet stick.

Wouldn't be allowed in F.A.S.T. only certain aftermarket heads are. But the idea is interesting!

 

[Cudadude2]

Fixing all those bad angles sucks to do but it can be done.

 

[RemCharger]

That's pretty cool

 

[ckessel]

Maybe a person could 3D print a better flowing manifold that looks oe, even with the casting numbers etc. Paint it with a solution contains very fine iron particles so a magnet sticks quite well.

 

[RemCharger]

Cut the visible top right off and build your short ram underneath