[n20ta2]

I'm dropping my original numbers matching 69 400 block from my gto to the machine shop tommorow to get it ready for my 461 kit. I purchased this rotating assembly used from a member here a couple years back, it has a forged crank (not sure of brand) eagle h beams and ross dished forged pistons .30 over. I bought an aluminum torque plate as I'm using kauffman HP heads, should I have him bore and hone with the torque plate installed? Also This block is a two bolt cap version,should I run main studs and have the mains honed? I was thinking of using king bearings for the mains and rods if there good? The block is getting zero decked and kauffman says with my 56cc highports I'm looking at just under 11:01 compression. Any other recommendations on this engine? I'm hoping for 650-700 hp with a northwind intake and 1050 carb, here is a pic of the cam card on the hydraulic roller I'm running. I may switch to a solid roller lifter on this cam if it's beneficial, thanks for any help!

[n20ta2]

Cam is a comp hydraulic roller 571 -571 lift 266int 270exh duration 110 lobe seperation

[AG]

My 400 stroker was making almost 700 Hp and the stock caps with studs were fretting. You might need billet caps at that level of power.

[steve25]

Your 2 bolt caps reguardless of running studs are the weak link once you get to the 650 hp level and above with a 3.750" stroke, no less the now greater stroke with the new Crank!

Two bolt caps are just plain iron like the block, atleast the factory 4 bolt caps where Armasteel and 30% stronger.

If you insist on having / needing to run 2 bolt studded caps and that stroke Crank at the 700 hp level then you better plan on running 6.800" long Aluminum Rods and getting the Crank balanced by a race shop that does not balance to the normal grocery getter car distance of 3", but 1.5".

[mgarblik]

If you are serious about actually making near 700 HP, you will need various upgrades to a 2-bolt block to make it live. Answers to your questions: Torque plate. If the shop has a boring mill that can bore with a plate, great. Most do not. My boring mill does not. I leave .007"-.008 to hone with the plates in the Cylinder King after boring. No issue. Very important that the machine shop have the exact head gasket you are going to use and the exact fasteners you will use with the heads for the torque plate. Concerning the mains: At 700 HP, all the main pins need to be removed and replaced with long pins. I feel you need billet splayed caps and studs at all locations for 700 HP. Stock 2-bolt caps with studs are on life support at 600-650 HP. Straight billet caps are on life support right at 700 HP. Line hone will be mandatory as soon as you change fasteners from stock. To be 100% honest, IMO at a true 700 HP you are right at that point where an aftermarket block would offer many advantages. King bearings are great. You mentioned the rotating assembly was used parts? If that's the case and the rods are Eagle, I would absolutely have them torqued up and checked for twist, taper and out of round. They tend to move around quite a bit initially, and then finally take a set. You will probably have to resize the big ends. If you back off the power level a little and stay around 6500 RPM's, the stock block will live with the improvements mentioned. Good luck with the build.

[n20ta2]

Thanks for the advice, I'm guessing on the hp, it may only make 600. The heads are untouched high ports from Kauffman. Do I need the head gaskets for the zero deck setup? I certainly am not against changing the caps if needed for sure. Question For you experts am I even in the realm of 700 with my heads and cam? Or am I dreaming lol if you think I may touch that level I will upgrade the caps. I will get him my head studs for the bore and hone, he said he could do both with the torque plate. He is also checking over the entire rotating assembly and getting it rebalanced.

[n20ta2]

I just got off the phone with Jeff Kauffman to order my head studs and gaskets, his guess on my combo would be north of 650 hp so he also suggested going with a set of 4 bolt caps I really appreciate all the advice and Im going to order them tonight too..

[68azbird]

i got a factory 68 block
looking to make 1200 to 1500 hp
what do i have to do?

[Dragncar]

Originally Posted by 68azbird

i got a factory 68 block
looking to make 1200 to 1500 hp
what do i have to do?

Buy a aftermarket block.

[n20ta2]

Unfortunately my local machine shop isn't equipped to line bore so I have to take it to a shop in Whitman Ma about an hr away to get that done.

[steve25]

You do not want a Bore job since that moves the Crank center closer to the Cam, it should be honed!

[mgarblik]

Originally Posted by steve25

You do not want a Bore job since that moves the Crank center closer to the Cam, it should be honed!

If he is going with aftermarket billet caps he has no choice. The shop doing the line bore hopefully will do the job correctly and the C-C will only change about .002-.003". When I set-up to line bore, I set the carbide cutter to just touch the saddle in the block. Then back it off .005-.006. So when you bore, ALL the stock removal is from the cap. This leaves the housing bores small, but no stock removal from the block. Then, I bore the thrust face on the #4 cap as perfect to size as possible. Again, I use layout dye on the block vertical surface and just kiss the layout dye. Can usually get +-.001. Now the block will need the front and rear cap cut .003-.004". Then line hone all the mains to the finished size. You end up with minimal stock removal, excellent finish and perfect sized housings doing it this way. It's a 5-6 hour operation start to finish doing this with my manual Sunnen equipment. That's why it's expensive.

[steve25]

Yup! I ment to say that final step needs to be hone.

[steve25]

Looking to make 1200 to 1500 hp for how long?

[73LeMans]

Originally Posted by n20ta2

Unfortunately my local machine shop isn't equipped to line bore so I have to take it to a shop in Whitman Ma about an hr away to get that done.

Not sure where on the Cape you are, but Custom Automotive Machine in South Weymouth and Circle Performance in Berkley that can also do this work. Just some folks to call if Reids cant do it fast enough. Just FYI

[n20ta2]

Oh great!! Any one of those shops better then another? Reids was reccomend but I'm open to suggestions if I can get a better job in the end. This is my first real pontiac build since a stock rebuild I did on my 72 gto back in 1993. Im accustomed to high hp chevy sb so I'm really looking forward to this challenge.

[73LeMans]

Originally Posted by 68azbird

i got a factory 68 block
looking to make 1200 to 1500 hp
what do i have to do?

Originally Posted by Dragncar

Buy a aftermarket block.

I agree with this advice. I put Program splayed 4 bolt caps in my 68 400 2 bolt block, but as mentioned, there was a ton of time invested to bore, cut the thrust to perfection and align hone. Then you have the cost of the caps.

When complete, my machine shop bill was close to that of an aftermarket block. The ONLY reason I kept this block was some stupid sentimental attachment and getting to say "hey, its a factory block" making 750 now. Maybe. It certainly didn't make any financial sense.

With any more power, and even some less, Id go aftermarket and take advantage of the goodies that block has to offer. I can't speak to what's needed to setup an aftermarket block to work, (it may still require final machining) but at least then you can step on the gas with confidence instead of being on the edge of anything breaking.

[73LeMans]

Originally Posted by n20ta2

Oh great!! Any one of those shops better then another? Reids was reccomend but I'm open to suggestions if I can get a better job in the end. This is my first real pontiac build since a stock rebuild I did on my 72 gto back in 1993. Im accustomed to high hp chevy sb so I'm really looking forward to this challenge.

Sorry, didn't mean to add any stress! I just know all of these shops are super solid, and are usually booked many months out. If one was busy, you had options.

[RAIV55]

Originally Posted by steve25

getting the Crank balanced by a race shop that does not balance to the normal grocery getter car distance of 3", but 1.5".

Please explain^^^

[n20ta2]

Yeah I was curious on that post too, I would definitely like to be informed when I talk to the machinist about the values used in balancing my rotating assembly.