[455rebel]

Still gathering up the last few parts for my winter 455 build. Trying to decide on my voo doo 703 vs 704. If 5200rpm, is my max Safe red line, I c no reason to use the larger cam. Is 5200 it, or are short burst any higher safe? And are the rods the liminting factor? Not trying to build a race car, just gobs of TQ from idle to bout 5k. On a budget .

[76TA462]

A while back on my 455 with same pistons as you are using, and also resized stock rods and ARP bolts I never suffered from running up to 5700 rpm or so. A few times I have slipped up and bounced well past 6000 rpm (I recall 6200-6300) with no consequences although it scared the beejees out of me. I have since changed rods etc. but still use the max dyno-ed power as my guide and stay lower than, say 5700 rpm simply because my torque starts falling off at about 4700 and my hp starts leveling about 5500 rpm but I don't fear hitting high 5s. That said, I started using an MSD box with rev limiter a while back. Others with more knowledge on this might have better advice to offer, but this is my practical experience and 5200 rpm, although possibly an optimum point for you to shift, still leaves you room. For what it is worth, factory gauges yellow-line at 5250 rpm and red-line at 5750.

[JLMounce]

Same setup here, the engine sees 5700 rpm regularly. It gets bounced off the 6000 rpm rev limit occasionally. No issues thus far.

It's my understanding that the rods themselves are not necessarily the limiting factor here. What typically happens is the factory rod bolts stretch too much, or fail all together as the tensile loads increase then you get things like a bearing that spins and locks the rod in place. It's at that point things snap.

If you shoot for peak power around 5300 with a shift point of 5500-5700 and maintain the engine properly, you should have years of good service in my opinion.

[ta man]

5500 rpm is pretty safe..I put many many passes on my old 462 shortblock. A rev limiter is an absolute must.

[Skip Fix]

My first 455 with the RAIV heads HP peak was 6000 and I routinely shifted it at 6200 with side beam polished rods that had new bolts. Rods are in the mild 400 in the 81 TA now.

[1967Tempest]

Originally Posted by 455rebel

Still gathering up the last few parts for my winter 455 build. Trying to decide on my voo doo 703 vs 704. If 5200rpm, is my max Safe red line, I c no reason to use the larger cam. Is 5200 it, or are short burst any higher safe? And are the rods the liminting factor? Not trying to build a race car, just gobs of TQ from idle to bout 5k. On a budget .

My 468 with 704 cam regularly sees 6K, but I have forged rods. Youll love the 704 in that engine!!!!

[Firebob]

The rpm limit will be the point that the weakest link decides to let go. No one can tell you what that will be.

[b-man]

I ran my cast rods/pistons 8.6:1 455 bracket race engine with a fairly big hydraulic cam, the H-O Racing HC-03 (244/252 @ .050, .550”/.554”) and always shifted at 5200. It would see about 5700 at the finish line, on a couple of occasions it hit 6k during a burnout.

Put the bigger cam in there and observe a 5200 redline, it’s really not going to make you run any quicker at the ‘stoplight Grand Prix’ shifting it higher than that.

[ponyakr]

Originally Posted by ta man

5500 rpm is pretty safe..I put many many passes on my old 462 shortblock. A rev limiter is an absolute must.

^^^THIS^^^^

["QUICK-SILVER"]

Originally Posted by 76TA462

For what it is worth, factory gauges yellow-line at 5250 rpm and red-line at 5750.

The factory red-line for 455's was for the cast pistons not the rods.

If this new build is going to retain the log manifolds, I'd do what it takes to keep overlap around 55°. That's at advertised duration. If the voodoo cams have more, I'd get Lunati to grind one on a wider lobe seperation angle.

Clay

[Mike Davis]

The factory rods are not bad. They do get a bad rap though. Years ago I ran a set in a .060 over 400. We used to use Mopar bolts because no one made an aftermarket Pontiac bolt.
Engine was 412"
400 .060 with Speed Pro Forged Flat Tops
Factory rods, beams polished, shot peened and resized.
Factory N 4813 crank
62 heads that flowed 260CFM

Ran a 200 shot of NOS through it and shifted at 6300.
Had over 750 passes and never let go.

I think the biggest issue is the pre of the rotating assembly.

A GOOD rod recondition, along with removing the casting lines on the beams, and a good balance job and the right clearances will tremendously help. Most people just slap stuff together then when it goes south blame the rods.

If starting from scratch of course new rods are the way to go.

[Formulajones]

Years back we ran a couple of 455's, with stock resized rods with ARP bolts, and forged TRW pistons to 5800 all the time. Had a 6200 rev limit chip in it. Solid flat tappet in it. Shift light was at 5800 so the shifts were probably occurring around 59-6000 by the time the shifter was moved.

Raced the car like that for many years without an issue, as well as thousands of street miles.

My current RAIII bird is stock rods, resized with ARP bolts and TRW forged pistons on the ends. I race it all the time, and although it runs it's best times shifting around 5200 rpm, I've tried shifting as high as 57-5800 looking for ET, and I don't even worry about the rods, the puny 068 cam gives up long before that.

[steve25]

You can replace the heavy 250 gram wrist pins in those Pistons with 194 gram pins from Butler and gain a very very safe shift point of 5500 rpm if need be, but note that even with fully ported iron heads D- port heads flowing some 260 cfm@28" and the needed 230 duration street Cam your still not going to be making peak Hp at 5500, you will be on the down side of the power curve!

The big square balancing pad on the small end of each rod can be for the most part removed which will lighten things up even more and add life to the Rods!

[455rebel]

Originally Posted by 1967Tempest

My 468 with 704 cam regularly sees 6K, but I have forged rods. Youll love the 704 in that engine!!!!

So with 3:15 gears, and stock converter, it will pull hard from idle?with 704.
Did you consider the 703?
What would I be giving up with the 703? 20HP on the top? Another 500rpm?
I want this thing to be really street friendly, daughter, and wife can drive it?

And I'll probably set a rev limiter for 5500.
And tweak my governor to shift at 52-5300.
My AMC colum shift, hooked to GM turbo 400 linkage ant real smooth.
Even at the track, it shifts itself at WOT.

[455rebel]

Originally Posted by "QUICK-SILVER"

The factory red-line for 455's was for the cast pistons not the rods.

If this new build is going to retain the log manifolds, I'd do what it takes to keep overlap around 55°. That's at advertised duration. If the voodoo cams have more, I'd get Lunati to grind one on a wider lobe seperation angle.

Clay

I bought a used set of ceramic coated firebird headers, I'm going to attempt to fit. Plenty of room up top, but the AMC uses a strut rod down low to set caster.
If the bird headers hug the block like the logs, I think I'll be ok. I've heard the headers are worth bout 20HP.

[shaker455]

Originally Posted by 455rebel

So with 3:15 gears, and stock converter, it will pull hard from idle?with 704.
Did you consider the 703?
What would I be giving up with the 703? 20HP on the top? Another 500rpm?
I want this thing to be really street friendly, daughter, and wife can drive it?

And I'll probably set a rev limiter for 5500.
And tweak my governor to shift at 52-5300.
My AMC colum shift, hooked to GM turbo 400 linkage ant real smooth.
Even at the track, it shifts itself at WOT.

I've used both 703 & 704.
If your going 455 then use 704.
703 is good for smaller cubes like a 400

[455rebel]

[QUOTE=steve25;6088923]You can replace the heavy 250 gram wrist pins in those Pistons with 194 gram pins from Butler and gain a very very safe shift point of 5500 rpm if need be, but note that even with fully ported iron heads D- port heads flowing some 260 cfm@28" and the needed 230 duration street Cam your still not going to be making peak Hp at 5500, you will be on the down side of the power curve!

That's why I'm considering the 703, I ant going to shift past 52-5300.
And the 703 would be a tad easier on the valve train.
And probably work better with my stock converter?

[shaker455]

703 is smoother & has better vac @ idle so it would be a little easier with a stock converter.
704 is rougher idle & less vac but can work with stock also...it will have more mid & top end HP & Tq

[1967Tempest]

Originally Posted by 455rebel

So with 3:15 gears, and stock converter, it will pull hard from idle?with 704.
Did you consider the 703?
What would I be giving up with the 703? 20HP on the top? Another 500rpm?
I want this thing to be really street friendly, daughter, and wife can drive it?

And I'll probably set a rev limiter for 5500.
And tweak my governor to shift at 52-5300.
My AMC colum shift, hooked to GM turbo 400 linkage ant real smooth.
Even at the track, it shifts itself at WOT.

Should, depending on the torque converter. I did consider both the 703 and the 705. I thought I would be leaving too much on the table with 703. I really wanted to go with the 705. I'm glad I did not. I had a 3.23 rear last year and have a 3.50 Eaton TruTrac in her now. The second you hit the powerband the car instantly flys!!!

That said, the 704 has poor street manners. My first gear in the TKO is 3.27. so there is a lot of clutch feathering to NOT do an instant burnout. She kinda surges below 1500-1600 RPM. Once you broach past that hang on.

I can imagine, that the auto trans will make it easier to drive in traffic. All I can say about the 704 is this, This is the first engine combo that I have ever had of my own, that will boil off the tires from 55 MPH. Going 55 in 5th gear and downshifting into 3rd to do a pull and the tires spin. Truly fun to drive!!!!

I'm Sure part of my issue there is teenie tiny tires in the back. I have a driverside 1/4 panel issue that will be resolved when she gets restored..

[455rebel]

That said, the 704 has poor street manners. My first gear in the TKO is 3.27. so there is a lot of clutch feathering to NOT do an instant burnout. She kinda surges below 1500-1600 RPM. Once you broach past that hang on.

So what if I do go with the 704, and advance it 2 degrees? Would that lower that 15-1600 surge a bit? I've degreed in many cams, but I don't really understand all the math? (What happens when you move or change numbers), I do understand lift and duration @.050.
I've read that advancing a cam 2 degrees, lowers the power band bout 500rpm?