Here are a few observations. In response to your post, I went downstairs and unwrapped my spare 509 block to check for you. First, I think all blocks of a given cast number are cast the same. They can machined differently, into different part numbers, but I think they have to be the same casting. MY 509 block does NOT have the third freeze plug hole, nor a pad for one. Besides the long casting number, ending in "509", it is cast merely, "509" (the three digits, only) on both sides of the block, encroaching on where the third plug would go. Also, the area that would be covered by the timing cover, has "020" and "010" cast into it, indicating a desirable metalurgy. Although I have no specific knowledge, either way, I find it hard to believe that this isn't as good (and better than some) a candidate for stroking as any production block. I question the accuracy of the machine shop's advice. This information, I've given is cause for you to check even deeper. I wish I had a "final answer" for you. If you find concrete answers, contrary to what I have suggested, I would like to hear about it.
The practical limit for a production block, as far as I know, is a 4.00" stroke. That makes a 427 with the standard 4.125" bore or a 434 with a .030" overbore. Generally, .030" is the largest practical bore on the production block.
Splayed is probably the way to go. A lot depends on the final stroke and how high you intend wind it. Actual hp numbers are fairly moot. It is the forces against the block caused by the stroke (linear increase) and the speed (increases with the square of the increase in speed) that determine the load on the block. Some on here will tell you it's an absolute necessity.
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My engine builder say he does not recomend stroking a 2-bolt 509 casting 400, has anyone done this?
Of course this cast number isn't available in a 4 bolt. But don't even THINK about building a 4 bolt 400 for very high performance. Good luck, and...
I noticed that a couple of hours after this post, you listed a short block with this casting number for sale. Do you have another block you are considering stroking? Or have you found negitive information on this casting?
Evidently there are 509 casting blocks that have only 2-freeze plugs (I have this version) 509 casting 3-freeze plug or 509 casting 2-freeze plugs with a "pad" for another freeze plug configurations. The 3-freeze plug or 2 with a pad 509 blocks, I am told by two different sources, are the best for stroking.
The block I was about to buy was a 3-freeze plug version that unfortunately is already bored .030 so I have ruled this out.
I do know that there are variations in the 509 blocks for the starter mount hole configurations because I have had two 509 casting 400 blocks with different starter mount holes.
Then I was led onto a Dart 400 iron block that was for sale but turned out to be a bad lead.
They said I COULD stroke my 2-freeze plug 509 block but that it is very tricky with the water jackets and they would advise using a better block suited for stroking and handling the HP of a 434. I am not taking any more risks on future engines, too much bad karma on the 406.
So the search continues, I'm in no rush.................
a stock 400 can take the stroke very easily but you have to be carefull with parts selection to make it easier and carefull with the grinding also the block it self should hold up to 600 hp stock form below 6000 rpm any thing more than that you should use aftermarket splayed cap setup once you go over about 14. comp the main webbings start to develope cracks not to good keep the comp under 13 and it should live there are thousands of old outlaw sprints out there built from stock 400 blocks pushing up to 1000hp :cheers:
Thanks for the feedback. I am suprised to hear that the "509" block was cast in more then one way. I have always assumed, that all the castings of like numbers, were the same. The fact that my "509" block is a two freeze plug version, like yours, tends to support that.
Concerning starter mounting, I am aware of two SBC bolt patterns. One has the two bolts, directly across from one another. A line between these two holes runs perpendicular to the crank centerline. The other starter mounts with two holes, but one hole is further ahead of the other. One bolt hole is common to both bolt patterns. Most blocks, I have seen have all three holes drilled and tapped. Could the difference you saw, be a two hole vs a three hole bolt pattern? Did you even pay that close attention, if you weren't specifically looking at that?
Thanks for the info. I am going to keep my ear to the ground for further elaboration on the two different castings with the common number. Good luck, and...
If you are really thinking about going 420 or larger, consider that you will need a killer set of heads to get the full potential out of it.
I've heard that to get the full potential out of anything bigger than a 406 requires heads that flow in the neighborhood of 18 or 15 deg pieces. I've also heard that if you are looking to make upwards of 600 hp, you really should consider an aftermarket block. And if machining costs are anything like they are here in NY, the aftermarket block is a pretty good value, especially if you are going to stroke it beyond 3.75. FWIW, those are things i've heard.
out of curiosity, why wouldnt you want to build a hi performance motor out of a 4 bolt main 400 sbc? i would think it would be better than the 2 bolt blocks :confused: did the 4 bolt blocks have a weak point in them that i dont know about?
If you are really thinking about going 420 or larger, consider that you will need a killer set of heads to get the full potential out of it.
I've heard that to get the full potential out of anything bigger than a 406 requires heads that flow in the neighborhood of 18 or 15 deg pieces. I've also heard that if you are looking to make upwards of 600 hp, you really should consider an aftermarket block. And if machining costs are anything like they are here in NY, the aftermarket block is a pretty good value, especially if you are going to stroke it beyond 3.75. FWIW, those are things i've heard.
Hey Ralph, I am in search of an aftermarket block to go with a 3.875 to 4.00 stroke crank, no rush but maybe by this time next year I will have a new setup to drop in, 427 or even a 434.
Id85,
Somewhere, very recently,I read a post from someone who either has or is building an engine, utilizing the "much desired" (his words) "509" block. I was going to post or e-mail this to you, but I got side tracked. If I see it again, or remember where I saw it, I'll be sure to contact you. I am NOT trying to prove a point or argue with your machine shop. I am just trying to educate myself, and I thought I'd pass it along.
since your going the hi-po route, have you thought about a new GM rocket block for $2300?? everything is already done and it can be stroked to 4.25" fairly easily. lots of advantages, priority main oiling, spread pan rail, raised cam bore and either side starter mounts. there are more and more 454 small blocks starting to show up. Brian
since your going the hi-po route, have you thought about a new GM rocket block for $2300?? everything is already done and it can be stroked to 4.25" fairly easily. lots of advantages, priority main oiling, spread pan rail, raised cam bore and either side starter mounts. there are more and more 454 small blocks starting to show up. Brian
Brian yes I have looked at that block and am saving $$$ so I can go the extra mile,,, I just built the 406 this year so it may take all of 2004 to come up with the $$$ casue the head angle and some other speed parts will need to be different/better than the components that I now have.
It is in the first or second paragraph of the first post. If that block will stand up to Jesse's (ski_down_it) kind of horsepower, I know it'll be OK for me. 10.0s-10.1s? I doubt I'll be anywhere near that. I just want a legit 13 at my home tracks altitude.
Larry,
i would not worry about the power the 509 block can handle, start looking at the rear end. the stock blocks can take far more power than the rest of the drive train. as far as the new rocket blocks, most of your SB parts will cross over. i am in the planning stages of a 454 SB all aluminum motor to put in the car. it should be fun, but then again an all aluminum 572 would be sweet under the hood of a '66 Chevelle with a 14 bolt rear end. Brian
Corvette Store
Stroking a 509 casting 400 SBC?
