1985 351w redline
Senior User
Joined: Aug 2011
Posts: 448
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From: Dearborn Heights, MI
Not sure exactly...I dont think there is a "rev limiter" with the carbed motors other than your right foot...My 88 has been carbed and i never spun it past 5500RPMs...I shifted it between 4800-5200RPMs...Even now my motor has been rebuilt, i still wouldnt take it over 5500, but its alll in where it makes it power.
DD: 84 F250XL supercab 2wd, T19, 3.54s 420 cu in IH idi, 175k
Project: 88 Bronco XLT, 358w, C6, 4.10s, 55k original miles
Toy: 08 Kawisaki KFX450R, Full DRD pipe
DD: 84 F250XL supercab 2wd, T19, 3.54s 420 cu in IH idi, 175k
Project: 88 Bronco XLT, 358w, C6, 4.10s, 55k original miles
Toy: 08 Kawisaki KFX450R, Full DRD pipe
Posting Guru
Joined: Aug 2009
Posts: 2,271
Likes: 2
From: Mexia, TX
Stock tach maxes out at 6K...though on an old motor I probably wouldn't take it over 4K. if it's been rebuilt it might be different, but in stock, 25-30 year old shape, you're gonna probably end up throwing rods or blowing stuff up if you get too high up there.
At least that's how I look at it.
At least that's how I look at it.
Elder User
Joined: Jan 2010
Posts: 590
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Stock tach maxes out at 6K...though on an old motor I probably wouldn't take it over 4K. if it's been rebuilt it might be different, but in stock, 25-30 year old shape, you're gonna probably end up throwing rods or blowing stuff up if you get too high up there.
At least that's how I look at it.
At least that's how I look at it.
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
The valvetrain is the limiting factor and it is "safe" to about 6000rpm, but the heads become a major choke point starting at as low as 4000rpm so there's really no point spinning it any harder than that.
Senior User
Joined: Aug 2011
Posts: 448
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From: Dearborn Heights, MI
Plus another factor is where the powerband is...My 358(351w), i could probably spin it deep into the 6000 range and it would be just fine. But its been built for low end torque, my cam and intake along with my heads(93 Lightning GT40s) operating range is roughly 1500-5800. So taking it past that is pointless. When I fist got it running, it had a old Iron 2bbl intake and man it fell flat on its face and skinned her knees after only 3000rpms!
...but once i threw on the Wieand aluminum...nite and day diff. she pulled hard all the way to 5000, like a freight train. but again u could tell there wasnt much more to be had over 5000.
DD: 84 F250XL Supercab 2wd, 420cu in IH idi, T-19, 3.54s, 175k
PRoject: 88 Bronco XLT, 358w, Built C6, 4.10s, 55k original miles
Toy: 2008 Kawisaki KFX450R, stock other than full DRD pipe
...but once i threw on the Wieand aluminum...nite and day diff. she pulled hard all the way to 5000, like a freight train. but again u could tell there wasnt much more to be had over 5000.DD: 84 F250XL Supercab 2wd, 420cu in IH idi, T-19, 3.54s, 175k
PRoject: 88 Bronco XLT, 358w, Built C6, 4.10s, 55k original miles
Toy: 2008 Kawisaki KFX450R, stock other than full DRD pipe
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