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I took a load of parts to the machine shop this morning. After having a pretty bad machine shop experience a few years ago, I now tend to go with shops who specialize in a certain marque, so for A-series and B-series stuff, I drive 1-1/2 hours north to Riverside to get the expertise of David Anton at Advanced Performance Technology (APT). Some of you have likely heard of him, as David Vizard was one of the founding partners of APT. Depending on who you speak to, Anton was really the A-series expertise that Vizard leveraged for his books.....or, so I've been told. Never the less, APT has a great reputation over here for developing and producing high-quality cams and lifters that are used by a lot of the vintage racing crowd.

The block is a pre-A+ 1275 with a standard bore. It will be bored +.020" for new AE pistons, and the rotating assembly will be balanced with a new MiniSpares lightweight flywheel, lightweight pressure plate, and Cooper S balancer. The rods will be resized, and fitted with ARP bolts.

The heads in the picture are a pair of 12g940 heads that came with my black Cooper 'S'. The guy I bought the S from bought them out of England, and paid nearly $700 each for them in 1982!! they are beautifully ported, and I was hoping to use one of them on my engine, but when David looked at them, he said they had been shaved down too far, and he didn't feel comfortable with them on a street engine. He explained the science behind combustion chamber shaping, and he said that even using a thicker Cometic head gasket would not give desirable behavior.

I picked up a standard, late model 12G940 from a friend of mine on the way home, and I'll likely be shipping that up to APT to be pocket-ported, and cleaned up for use....bummer!

Is that the Riverside next to Corona & close to Ontario airport ?

JC T ONE wrote:Is that the Riverside next to Corona & close to Ontario airport ?

Yep, to the east of Los Angeles.

Benny wrote:

JC T ONE wrote:Is that the Riverside next to Corona & close to Ontario airport ?

Yep, to the east of Los Angeles.

was there a couple of years ago, my friend Anders lives there.



what are those 2 round things, between your flywheel & pressureplate ?

JC T ONE wrote:
what are those 2 round things, between your flywheel & pressureplate ?

2-piece Cooper S harmonic balancer

Hey Benny it looks like we are in the same situation. "I'm on the east coast" and too trying to find a special shop that I can trust is hard to find.
Just curious are those bolts on the mains on the 1275 A block?
Have fun hope all goes better, all the best from here on the east coast.
Scott

Hi Benny,
The block you have is the one with the opening above the center main. Whilst many have used them, I consider they are not the strongest version available for modifying. If I had one without the opening and I was building a higher performance engine, I would be using it.

Regards
Al

scott6058 wrote:Hey Benny it looks like we are in the same situation. "I'm on the east coast" and too trying to find a special shop that I can trust is hard to find.
Just curious are those bolts on the mains on the 1275 A block?

Scott,

Machine shops are closing down at an alarming rate in my neck of the woods. A couple of years ago, I contacted a friend who worked at Cosworth in LA, figuring that there were surely dozens of good shops still in the LA area.....he wrote back saying "It's not much different up here!".

I had a small block Ford built last year (for my Cortina) by a guy in Illinios, and it only cost me $150 to get shipped to San Diego on a pallet through one of these private freight companies. David at APT says he has people Fed-Ex'ing him A-series parts from all over the country, so that might be an option for you.

To answer your question, the non-S blocks used bolts, while the S blocks used studs.....IIRC.

Al,

Unless you are talking about the hole for the cam bearing, I'm not seeing the hole you are referring to. David asked me what my intentions were for the block, and I trust him to alert me to any concerns he has. Plus, 1275 blocks aren't the easiest thing to find here.

66S wrote:Hi Benny,
The block you have is the one with the opening above the center main. Whilst many have used them, I consider they are not the strongest version available for modifying. If I had one without the opening and I was building a higher performance engine, I would be using it.

Regards
Al

al, have you ever seen one of these blocks crack through this hole?

i never have and it would be interesting to know if this genuinely happens, or if its just a bit of 'vizard talk'

Could it be that although they don't crack, they move around more, wearing out the bearings faster? Spinning mains?

Vegard wrote:Could it be that although they don't crack, they move around more, wearing out the bearings faster? Spinning mains?

but again, is this true, or is it just an old wives tale repeated again and again?

Vegard wrote:Could it be that although they don't crack, they move around more, wearing out the bearings faster? Spinning mains?

David did mention that the center main tends to drop on A-series blocks by a few thou, to where they benefit from being align honed. He said most "seasoned" blocks will have their cranks reinstalled, and while it will spin just fine, you can sense a bit of drag. After being aling honed, he says you can spin them, and the crank will continue to spin for a few seconds on its own.

I got the sense that once this "drop" had occured, and been corrected, it would not continue on until failure. He also didn't mention whether later blocks were any better for this....perhaps they are?

Hi Guys,
The thought here is that these blocks are not as torsionally rigid and this in turn leads to crankshaft failure. I have seen a block with the upper bearing tunnel torn from the web but I am not sure that it is common. I wasn't aware that Vizard has commented on this subject but I respect his opinions and generally find them to some substance.

Regards
Al

Benny wrote: Al,

Unless you are talking about the hole for the cam bearing, I'm not seeing the hole you are referring to. David asked me what my intentions were for the block, and I trust him to alert me to any concerns he has. Plus, 1275 blocks aren't the easiest thing to find here.

Hi Benny,
The opening the talk is about is directly above (below as viewed in the pic) the center main journal in the block. Earlier and later blocks did not have it.

Al

Benny wrote:To answer your question, the non-S blocks used bolts, while the S blocks used studs.....IIRC.

Not quite, S blocks had both during their production run. It would depend on what type of block you have. All 1071 blocks I have seen have been built up with bolts instead of studs.

masnarda wrote:

Benny wrote:To answer your question, the non-S blocks used bolts, while the S blocks used studs.....IIRC.

Not quite, S blocks had both during their production run. It would depend on what type of block you have. All 1071 blocks I have seen have been built up with bolts instead of studs.

interesting. I'm just going through this process with the engine re conditioner and my 1071 has studs. Is there a reason they all have bolts?

Later 1071 and 970 blocks did indeed have studs fitted .