The best solution is obviously a 4 bolt main block, but that adds a lot of money. A main girdle is a good substitute. Kurt
Almost finished tearing down my engine and it looks like the block is toast. It'll definitely need .060 over, maybe more. The nut that holds down the oil pickup tube on one of the main studs came off and dinged up a couple pistons and the windage tray. Not sure if that's what caused it break... I haven't taken off the mains because I need a pulley puller to get the balancer off, but I think the crank and rods are ok. Here's some pics. A couple pistons look like this.... And all the rods have this flat spot in the same place... I was doing a lot of research over the weekend and I came up with 3 options for my new bottom end. 357w at 9.1:1 cr. 393w at 9.2:1 cr. Or 418w at 9.7:1 cr. I really like the 393 option, but that requires new crank, rods, and pistons. The 357 will use a stock crank which I should be able to get cheap with the new block, but I'll need new rods and pistons. The 418 is probably my best option since I can use my current forged crank and rods. Ross makes some -31cc dished pistons for a 418. If it's possible, I could have the combustion chambers on the heads opened up from 58cc to 64cc which would lower the compression to around 9.2:1. My only concern with the 418 and turbo is that it will make too much power. I suppose that shouldn't be a problem if I keep the boost low...
With a shorter throw, the internal stress created by high RPMs is lessened, making higher RPMs possible. That is one of the reasons why those F1 cars can run such high RPMs ... shorter crank throw. Also, less cubes means less exhaust. With 418 cubes and a turbo, I can imagine how the exhaust in the upper RPMs could overwhelm a turbo. What kind of RPMs do you like? A friend of mine has an M3 and he can stay in it up to 8000. The gears are around 3.90:1 or 4.10:1. That thing gets into the power band quickly and stays in it for a long time. If I was doing it again, I think I'd go with the 9:1 CR shorter throw 357 (stock crank) with a girdle, put my money into as light a rotating assembly and valvetrain as financially feasible and get a big mother turbo (or 2!) that spooled up around 3000-3200 RPM. Driving around would be like stock and gas-friendly, and it would be an absolute monster when you got into it.
My two main reasons for wanting to stick with the 418: Cost, since I'll just need new pistons, and it'll work a little better NA with my heads and intake. I like RPMs, but I plan on only going to 6000 with this setup. If I had the money for good parts a 8000 RPM 351 would be badass! I've driven my boss's 335i before and it's definitely fun, and pretty fast for only 300hp too. I don't think it goes up to 8k, but I know I hit at least 7k in it. I suppose I should just send Ed an email and get his opinion...
I think the turbo is a great idea. I worn you though, it's going to make a ton of power, and it's going to cost a pretty penny. A turbo system isn't cheap. My friend has a 325e, and my stock V6 F150 is faster than it. Kurt
2008 BMW 335i is a 300hp twin turbo 3.0L I6, 6-speed auto w/paddle shifters. Runs mid 13's stock. Not even close to a 325e.
My internet humor detector failed me lol I think I found a cheap .030 over '74 block here locally. I'll send Ed Curtis an email this weekend to see what he recommends, 357 or 418.
Yes, but the 418 is cheaper, has more compression, and may make way more power than I want. All signs point to the 357 as being the best performance option for me, but I'll need a whole new bottom end instead of just pistons...
I think Ed is going to point out the obvious. If more cid is cheaper, than that's what he is going to recommend. Kurt
were you going to source a used 351 anyway? that most likely have some of the things you would need (ie crank and rods)
Yeah, found two blocks. One is a freshly machined, never ran .030 over '74 block $150. It will need clearanced for the stroker crank tho..... Other one is an unknown year stock short block $200. I'm not going to run stock rods on a 600+ rwhp turbo setup so I'll be getting a set of H-beams if I go with that block. Plus I'll probably go .030 over so I'll need machine work done to it too.
Ok so here's the plan. Just waiting to hear back from Ed before I start buying parts. '74 block 418w 9.6:1 CR AFR 225 heads Vic5.8 intake FTI cam S400 75mm 1.10 A/R T6-83 The 1.10 A/R should spool really fast, but I'm worried it might choke at high RPM's. Since it's a street car I don't think it'll be a problem... Plus it's listed as supporting 950hp and I don't think I'll go much over 700... Or I could get a 1.32 A/R T6-96 for the same price...
