Looking to build a ~520 ci naturally aspirated, big block with Jon Kasse heads, roughly 11.25:1 compression ratio. Are there any stroker kits available and does anyone have any horsepower estimates for this build? Is it possible to get this cubic inch from a stock block?

 

Speedway
Summit
Scat all make or have 460 stroker kits
Not much if any block modifications needed (the 460 Ford is the easiest engine to stroke)
HP is a figure relative to your complete setup
Your camshaft and rpm range are the factors along with compression ratio and fuel type
You should be able to get 600 out of it pretty easy

 

521 or 545 are very easy to get from a stock block build. Any block will go to 4.390 bore size. Either stroke will fit with zero clearance work done on the block. If you do a 4.500 stroke I'd recommend springing for the steel crank to make balancing easier. This has improved somewhat but most of the time it takes some heavy metal to internally balance the cast 4.500 stroke crank with around a 2300 gram bob weight. The steel crank won't need heavy metal so that makes it not much more expensive.

A few years ago I did a 560 cubic inch engine for a customer who mud races. It had been a Dove headed 557 for about 15 years. On the new build I used a set of P51's and the engine made a little over 900 horsepower at about 6300rpm. (918 horsepower at 6350 and 808lbs/ft at 4800rpm) This was 13.5 compression with a solid roller but honestly I think that a pump gas build with similar specs otherwise and the correct cam could top 800 horsepower pretty easily.

The cam was 277-291 @ .050 on a 111 lobe sep in on 108. Lift was .735 -.747. These are old lobes that are very easy on the valvetrain.

 

Look at Ohio Crankshaft. I used one of their kits for my 502 build. All forged, balanced, BBC rod journals, H-beam connecting rods, SRP pistons, King bearings. I was very impressed.

 

How much was that kit ranger?
BBC rod journals? Chevtone rods?

 

Ohio Crankshaft does have pretty nice stuff for a good price. My friend Wes has one of their 4.600 cranks in his 618 and it has been run a lot.

 

It was $2300. Yes, big block chevy (BBC) size connecting rod journals on crankshaft. The connecting rods are Ohio Crankshaft brand.

Rotating Assemblies - Ohio Crankshaft

 

I wonder if they have pistons with the SCJ/P51 valve relief locations in an SRP? I know Mahle has them and I think Icon does as well.

 

Ohio Crankshaft will make sure you get the piston you need for your cylinder head. They advertise JE / SRP, and Diamond pistons, but can probably get whatever you need. When I called Ohio Crankshaft, the owner asked what cylinder heads I had. I told him I had Trick Flow TFS-53410001. He told me to give him a day, so he could research and make sure the pistons I wanted would work with my cylinder head and their rod combination. He called back same day.

 

That's good because I had a customer who built a 557 using the wrong pistons. He had a set of A429 heads and he used a Mahle piston with the SCJ valve relief. I cut new correct valve reliefs in the pistons so now they're "universal".

 

Looking for suggestions for sourcing bare blocks for this build. I should have clarified that this motor is intended for mostly street use. Have only found a racing block (Kasse $$$) and an eBay block that I don’t trust.
For the power I’m hoping to make (800hp), do I need to make any oiling system upgrades? Lastly, are these blocks 2- or 4- bolt mains?

 

If you're using a production block it makes no real difference which block you use. D9TE has a cylinder wall that is slightly longer (more like an SVO) but that's about the only significant difference. There are no differences in overbore capability. All production blocks are 2 bolt except for the Boss 429, SCJ and later CJ . DOVE-A blocks were made with main webbing that is designed to accept a 4 bolt cap but nearly all DOVE blocks are 2 bolt. Ryan Scott makes and sells a steel main cap that's made to convert the regular skinny web to 4 bolt.

Oiling system modifications are generally not necessary but depend on your choice of lifters. With some roller lifters I bush the right side lifter bores and put a restrictor in the cross over to control oil but most of the time this isn't necessary especially for the street.

With good cylinder heads, compression the right cam and 545-557 cubic inches the engine should be able to make 800 horsepower below 6500rpm.

 

Dave,
Does anyone machine the 2 bolt main caps down and then use studs and a support bar similar to a stud girdle? on those 429 blocks?

 

You can do that but it isn't worth the trouble. Lots of people used to do that including me but the halo doesn't do anything to add strength and studs don't clamp as well as bolts do.

 

Dave,
The halo you refer to is the U shaped piece?
I have a stud girdle thing on a home built 302 boss motor (2 bolt main)
I bought it from Pro Stock Engineering way back when '79 or '80
They said it made the 2 bolt block stronger? than the 4 bolt block?
I am taking your advice and getting a stroker crank for my 70 429 block
I had planned on getting my 2 bolt main caps machined and going the stud route
What should I do instead or should I leave it alone?
Thanks