[KEN CROCIE]

You are correct Tom S. #64 heads but one year only 455. rare.
you are correct Tom S. Big cams for ping control are somewhere between a crutch and a myth. BUT someone is going to jump in and say how well it worked for him.

[steve25]

Here’s my take for what it’s worth to anyone.

In terms of a pure street and limited strip motor of whatever displacement you care to make it under 440 cid , if it’s naturally aspirated and not making 175 psi of hot cranking compression then it’s not going to be much fun to drive below 3000 rpm even with something like 3.42 rear gears when where talking about cars of over 3600 lbs!

Street motor’s making under 160 psi rev like a 3 legged Dog unless your into non street friendly 4.11 gears!

[tom s]

Im not sure how big of cam your talking about but I have 3 engines running right at 175 pumping compression,in the 434 in range and 2 of them have OFs in them.No issue in lugging them at 1500 RPMs on the street with a stick shift trans and run great with 36 degree lead on our Calif 91 piss gas.2 of them are Dports with 2-4 tunnel rams and one is a RA V with big lazy ports which are supposed to suck at low RPMs.ANYONE in the So Cal area are always welcome to drive any of my cars.FWIW,Tom

[racerboy]

I'm sort of on the fence here now. I have another ongoing thread regarding the Icon 14cc dish pistons. Turns out my RA III was rebuilt with low-budget 8-eyebrow pistons as well as an MPT-1 cam (smaller than an 068). There is no question I am going to pull the motor. The big question is what direction do I go. Do I simply drop in the 428 as-is (maybe with a cam change), This will obviously require some block adapters, as well as a cam change. Personally, i hate the idea of 670 heads on a '70 Trans Am, but that's just the ADD in me. But then really build a stout 400 (or maybe a stroker) out of the WS block? I reached out to Butler and they said I could build it up to 461 with the #12 heads, and they could cut a Ross piston with a deep enough dish to run pump gas. I have some concerns about stroking the original WS block, but they assured me that there was no risk to the block. I could also leave the 400 alone for now and build the 428 up and throw the #12 heads on that, but I still have the frame adapter issue, and would eventually have to rebuild the WS anyway,. Any suggestions are appreciated. I would really like to drive the Trans Am this summer, so I would hate to leave it out of service for too long.

[steve25]

Don’t let the use of a motor mount adapter be part of your decisions it’s basically a non issues.

Here’s a way around that anyway!

[racerboy]

Thanks Steve!

[racerboy]

Just to be transparent, this is for a 1970 Trans Am (not sure of weight) with an M-20 and 3.55 12-bolt posi.

[racerboy]

Originally Posted by Cliff R

Since the build was done 20 years ago most likely the pistons are dished.

I had two different 428's in my car decades ago, one had #96's on it, the other 6X-4's. Both of those engines had dished pistons. In the first engine I ran a real 744 cam with high ratio rockers, in the second engine the HO Racing HC-01A.

The 744 cammed engine was "weak" below 3000rpm's and pretty much done by 5000rpm's. Not really impressive anyplace. The second one faired better, but both of those engines needed more compression for the cams I was using in them so I really wouldn't recommend going that direction unless you just want a decent running engine that will easily manage low octane fuel and move the car from point A to point B.......FWIW......

Thanks Cliff. Is there any way to tell if these are dished or not without taking off the heads? Maybe I should get one of those inexpensive borescope cameras. If it turns out they are dished, would it be possible to put in a decent cam and tun it as is with the 670s? I haven't run this engine for about 7 years, but when I did run it, I don't recall it pinging on 94 octane, but it had too much lump in it to really drive it on street. I definitely went with too big a cam, I just don't recall what it was, other than I think it was a Lunati. I distinctly remember it being more than an 041 cam. I guess I'd have to pull it for a final determination. I have a Crower 60423 kit sitting on the shelf. I was originally thinking of putting that in the 400 until I found out about the low-budget pistons in that motor. How do you think that cam would work in a 428 +.030 and 670 heads?

[Thegoatman455]

Originally Posted by KEN CROCIE

You are correct Tom S. #64 heads but one year only 455. rare.
you are correct Tom S. Big cams for ping control are somewhere between a crutch and a myth. BUT someone is going to jump in and say how well it worked for him.

I guess that leaves me to wonder the point of the Wallace dcr calculator. I’m kinda surprised by the response.

I recently got a cheap bore scope and it works great and find useful

[Stan Weiss]

DCR can help BUT the old GIGO comes into play.

Let look at a Pontiac 455 ci engine. It will have 175 psi cranking compression / 7.3:1 DCR

So how can I get there

8.5:1 / IVC 56 ABDC

9.5:1 / IVC 71 ABDC

10.5:1 / IVC 81 ABDC

11.5:1 / IVC 88 ABDC

12.5:1 / IVC 94 ABDC

Do you think because they all have the same DCR they will run the same?

Stan

[Thegoatman455]

I was under the impression for octane requirement, yes. ??

[racerboy]

Originally Posted by Thegoatman455

I recently got a cheap bore scope and it works great and find useful

What scope did you get? I did a Google search and found ones from $50 up to $500!


Sent from my iPhone using Tapatalk

[racerboy]

I took the oil pan, balancer and timing cover off of the 428. I’ve never pulled a cam before so I want to make sure I do the next steps right. Not sure if this is right order, but here goes:
1. Loosen all the rocker arms and then remove the pushrods and lifters. It’s important to keep these in order, correct? How do you manage that?

2. Remove timing chain/fuel pump eccentric.

There is no distributor in engine so I think that’s it. How do you actually get the cam out? Don’t you have to be super careful not to scratch the cam bearings?

My progress today:










Sent from my iPhone using Tapatalk

[Thegoatman455]

Originally Posted by racerboy

What scope did you get? I did a Google search and found ones from $50 up to $500!


Sent from my iPhone using Tapatalk

https://www.amazon.com/gp/aw/d/B087Q...images_section

[Jay S]

I would find a set of heads in the 90-100cc range, put the 60243 crower in the 428 and drive it, get the T/A back on the road. Look for 64 off of a 455, or off of a 400 or 350 look for 96, 7K3, 4C,4x or 6x. As long as the head has screw in studs I would not even care if it had 1.96 intake valves instead of 2.11s.


I would not do a bigger cam to try nurse the 670s along on your 428. I don’t think you will not be happy with it. The big cam becomes a crutch once the heads do not supply enough air/fuel for the engine for the desired rpms. 670s do not flow great in stock form at higher lifts, irc they are done at about .4”. With a big enough cam and no airflow to match, at some point the engine will loose cylinder pressure and spreading what cylinder pressure it has over more RPMs, making less power over a wider rpm range. Go to big on the cam and it can run like crap and won’t be fun to drive.

DCR is a guideline and a starting point. But you absolutely can not use it in totally different engine combo’s and expect to to tell you every little thing going on in the engine. Using the Wallace calculator for guidance the user needs watch the V/P index as well as the DCR numbers. Plus you must have to have an idea what the profile is going to do, intensity and actual numbers that are consistent to use it consistently. I use DCR and the V/P a lot, but is is one design criteria among many.

Just as example. A RA 4 cam has duration of about 292* @.006” tappet. It has 231* @.050. That is a difference of 61*. The intake is shutting at around the upper 70s. I just did a solid lifter cam in a mopar that has closer to 20* change in intensity from .006 to .050”. Totally different valve lift curves.

[racerboy]

Thanks Jay. If you had to choose between a 6X-4, 96, or 64, which would you go with? The 64 seems like the most expensive since it is a one-year only head, so not sure that makes the most sense, though i'm sure I could sell them if I decided to once I got the 400 finished.

[racerboy]

Got the heads off. Like Cliff said, these pistons have a round dish in the middle. They have part no. L2257 030. I think the 030 means .030 over, right?

I can’t seem to get the crank sprocket to slide forward at all to remove the timing chain. The cam sprocket slides but not the crank Is there a trick to this?





Sent from my iPhone using Tapatalk

[racerboy]

The pistons have some carbon on top. Do I have to get rid of that (and how)? Also I don’t think it is at zero-deck. It looks like when it is at TDC the piston is still a little below the deck.


Sent from my iPhone using Tapatalk

[racerboy]

Here is the #1 piston at TDC.


Sent from my iPhone using Tapatalk

[Jay S]

Originally Posted by racerboy

Thanks Jay. If you had to choose between a 6X-4, 96, or 64, which would you go with? The 64 seems like the most expensive since it is a one-year only head, so not sure that makes the most sense, though i'm sure I could sell them if I decided to once I got the 400 finished.

6x-4 is my first pick, best of the induction hardened seats, and the easiest to find. The 64s are rated at 87cc, but most of them run 91-93 cc, almost the same as a 6x-4. Also for some odd reason the 64s had a little bit smaller intake port and do not flow quite as much as the other D ports stock. I wouldn’t be picky though, any of those 90-100 heads would be fine to get you buy until the RA 3 is finished. Even a 6x-8 would be fine, a little lower on compression (101-103cc give or take) actually probably my 2nd pick is a 6x-8. Won’t miss the compression as much with the 428. The 96 and 7k3 often run 98cc, not much different than the 6x-8.

428 looks promising. IMO, looks clean, not enough carbon to worry about. Should be able to lightly pry the crank sprocket forward with a small pry bar lightly prying and tapping on the end of the crank with a rubber mallet while you pry..