[DeTomaso] Ford 392 rev limit?

[Julian Kift]

An engine builder once told me to use a rule of thumb limit of 4,000 fpm piston speed, which assuming you have a 4.030 bore by 3.85 stroke would equate to setting the rev limiter at 6,200, so looks like you are about right.
 
Julian
 
> From: MikeLDrew at aol.com
> Date: Wed, 4 Sep 2013 22:40:10 -0400
> To: detomaso at POCA.com
> Subject: [DeTomaso] Ford 392 rev limit?
> 
> Hi guys,
> 
> During the dark days when the forum was down, Jeff Cobb posted a query and 
> it was rejected, so he asked me to post it for him (below).   There are 
> actually two posts--start at the bottom one and work your way up.
> 
> Mike
> 
> ====
> 
> From: JEFFREY COBB <zumzum at cox.net>
> Subject: Re: 351 rev limit
> Date: August 29, 2013 1:54:13 PM CDT
> To: "detomaso at poca.com List" <detomaso at poca.com>
> Cc: Jeff Cobb <zumzum at cox.net>
> 
> Hello again about the rev limit question,
> The engine specs are:
> Ford Racing 392 Windsor stroked,
> 360 hp at rear wheels from the dyno sheet
> GT40 Heads--9.7:1,
> Mighty Demon 750
> Ford Racing steel flywheel
> Tremac TKO 3550 5 speed and 3.73,
> 
> Any help would be appreciated,
> Thanks,
> Jeff
> _________________________________________________________________________
> On Aug 29, 2013, at 6:13 AM, Jeff Cobb wrote:
> 
> 
> Hello group,
> 
> 
> 
> 
> 
> Hope you all can provide info.
> 
> 
> A 2000 Superformance Cobra came back in yesterday for some finish up work 
> while I was tuning up a 57 Ford Fairlane Skyliner with a Police Interceptor 
> 392 engine.
> 
> 
> Just bought by a faithful customer and he wants me to do what I want to do 
> to make it better and faster.
> 
> 
> 
> 
> 
> My question to you guys is about the safe rev limit. It has a 351 taken out 
> to a stated 392, the largest Demon carb I've ever seen and a MSD 6AL with a 
> 6100 rpm limit chip.
> 
> 
> 
> 
> 
> Problem is that this strong engine will instantly bang off the limiter too 
> quickly in the first three gears. Engine is very smooth at high rpm's and 
> feels as if it would rocket well past past 6,100 with no problem.
> 
> 
> 
> 
> 
> I do not know cam, rear end ratio, compression or any other specs and I 
> will try to find out today. Torque peak feels the  strongest about 3,000 to 
> 4,100 with 6,1000 coming in too soon.
> 
> 
> 
> 
> 
> What rpm limiter chip do you all recommend for what I have described?
> 
> 
> I have little history with higher rpm ceilings of large FORD engines.
> 
> 
> Owner is a 64 year old just math professor hot rodder who drives little and 
> want to have fun before his last personal rev limit.
> 
> 
> We don't desire to scatter his engine and he might buy and use some of my 
> VP 110 leaded race gas which will also help.
> 
> 
> 
> 
> 
> Thanks for any input,
> 
> 
> 
> 
> 
> Jeff Cobb
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