393 or 408

Am I correct in that there isn't anything significantly negative about a 408 in comparison with a 393 other than the rod ratio getting a bit more radical? My application would not be a daily driver.

Parts availability and cost might be factors, but BIG factors?

My thoughts are that the reason for building a stroker is to increase displacement, so why not go on up to the 408 as long as the rod ratio is "safe"? The 427 sounds a bit much in that regard.

Comments are appreciated.

I struggled with the same question for a long time. I'm building a 66 ranchero street/drag car & thought a 393 would be a good choice with regard to rod ratio & pistons. I'm deathly afraid of having another stroker where the wrist pin bore cuts into the oil control ring lands. I had a Rag-o-let 383 stroker that used a quart of oil every 120 miles. So I asked a lot of questions on this forum and others & found out that you can get pistons for a 408 that don't have this issue. Also, as I understand it, the longer 351 stroker rods provide more dwell at tdc & bdc to provide more hp. I ended up choosing a 408 kit with 6.250 rods from ADPerformance - Scat kit, all forged. Will let you know how it goes. I kind of expected it today, but it didn't come. Maybe in the next day or 2. I'll tell ya, Chilly460 has provided me with a great deal of stroker info. See if you can get his attention.

Rick

Thanks, Rick- I appreciate your reply. I'll certainly check back here in a few days if you'd like to post a response about how your project is coming along.

I should note that this is a blower application, so my desire to get the compression down there is going to affect my choice of parts as well.

One other point, you can build a really inexpensive 393 stroker with a just a stroker crank (3.75 I think), use stock 351 rods & stock 302 pistons, so the only expensive aftermarket piece you need is the crank. I intend to build something strong that I can miss gears in & not have to explain to my wife that I broke my expensive toy. This being the case, I wanted forged H-beam rods & as long as I was going to have to buy a crank & rods I figured that I should go with the 408. I'd elimenated all of the benefits of a 393 by using aftermarket rods.

Rick

3.85" stroke for a 393, if I remember right.

I think I'm with you on the H-beamers and forged crank. I'd want forged pistons also- might as well cover all the bases. The stock rods, cast crank, and forged pistons held up well with my blown 302, but man... it's always nice to have a solid feeling of knowing that it's all going to hold together. It takes so much work to put a motor together that passing up on some key components could end up being more costly in the long run, I'm sure.

I'm thinking more and more that if I am to go the stroker route, I would choose the 408. I'm going to have to do the in-depth on what parts are available and how they'll work with the combustion chambers of those heads to make SURE my compression ratio is around 8:1.

I was hoping to get a few more opinions on the 393/408 subject, but I suppose it all depends on what one is going to do with the motor. Maybe the question was too general.

Thanks again for your response. I hope your engine turns out killer and your wife is good with it all! [img]/phpBB/images/smiles/icon_smile.gif[/img]

Just got my stroker kit in from Scat (heads didn't come tho). All forged (crank, rods & pistons), the crank rings like a bell when you thump it. I've got a woodie that won't quit. All I need now is a block & I can get started.

Rick

HEE HEE! Excellent!! [img]/phpBB/images/smiles/icon_tup.gif[/img]

A 408 with 6.20 rods has the same 1.55/1 rod ratio as a 393 using stock rods.

To put it in perspective, the stock rod ratio for the Ford 4.9L (300 CID six banger) is 1.55
The stock rod ratio for the SBF 302 & 351W are both 1.7
The stock rod ratio on a 350 SBC is 1.6

[img]/phpBB/images/smiles/icon_smile.gif[/img]


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80 E-150, 408/351W, 600CFM/Performer, AOD, 4.11

<font size=-1>[ This Message was edited by: johnebli on 2/26/04 6:44pm ]</font>