351w rpm limit?

13786 Views 72 Replies 17 Participants Last post by 351windsail, 4 mo ago

Goinbroke2

Discussion Starter · Oct 15, 2020 (Edited)

First post here, just getting into 351w’s.
So, my bracket car (83 mustang gt) got laid up after blowing the 3rd engine in 4 years, having my first kid and buying a new house. It’s only been 22 years! I’ve raced everything from escorts to f150’s to 8.90 roadsters over the years. Just retired in July and the kids are gone, I’m getting the gt back out. Have a 460/c6 combo I was going to put in but decided to stick to sportsman for the first year or two.(13.5-20 et) I am NOT running another 8000rpm small block...ever! Want a 5500rpm big block ....but, in the meantime am looking at a 351w/p heads I have as well as a .512/[email protected] cam I have.
So, junkyard 351 with 750dp I have and 1 3/4 long tubes with aforementioned heads/ cam. Guessing 300 hp, that puts me at 110mph and with my 4.86’s, about 6400.
Wild guess, but would the stock bottom end hold that? I’m guessing no but would like a second opinion. It has a 9” out of a 76 bronco and I have a set of 3.50 gears too.
I’m thinking that cam won’t wind the 351 up(still making power) past 6000 so maybe go 3.50’s anyway. How’s that for a first post? Lol!

What rpm will a stock Windsor handle.(repeatedly)

1 - 20 of 73 Posts

408foureye

· #2 · Oct 16, 2020

Stock bearing clearances, rod bolts and factory cast pistons are the issue IMO. If you aren't going to touch the bottom end, I would keep it under 6200 to be safe. I ran a rebuilt mostly stock bottom 351w in a road race car for a few years and regularly spun it up to 6700 with the occasional missed shift bouncing off the 7k limiter.

It was a fairly basic build. Stock 28oz crank mains @.003" and rods @.0025" w/ clevite p series bearings, stock rods w/ upgraded arp bolts, KB hyper pistons in stock bore flex honed cylinders, stock style massaged melling oil pump, afr 185 heads w/8019 springs, modified stock lifters, anderson n71 cam, vic jr intake, 700 holley dp, large oil cooler to keep oil temps down and t sump canton pan which probably helped it survive. Car ran great and had lots of midrange grunt. Powerband carried well past the shift point. Never dynoed it but I would say it easily had close to 400 at the wheels. i recently pulled the engine for a stroker build and was suprised to find the bearings looking like new.

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Ssp 363

· #3 · Oct 16, 2020

Well yeah with the right cam a valve train im sure you can spin pretty high. I would shoot for about 7krpm

tjm73

· #4 · Oct 16, 2020

My brother has a 418W in a stock block that sees 7000rpm every single time he drives it. Last time it was apart for refresh/rebuild (mo powah!!) it had only the slightest evidence of cap walk. Nothing to even get concerned about.

Reactions: 2

408foureye

· #5 · Oct 16, 2020

tjm73 said:
My brother has a 418W in a stock block that sees 7000rpm every single time he drives it. Last time it was apart for refresh/rebuild (mo powah!!) it had only the slightest evidence of cap walk. Nothing to even get concerned about.

Internal or 28 oz balance?

tjm73

· #6 · Oct 17, 2020

408foureye said:
Internal or 28 oz balance?

Internal.

Goinbroke2

Discussion Starter · #7 · Oct 18, 2020

So, I have a 88 efi 351 being dropped off on Monday evening, I guess that settles it, the 460 is officially waiting. Thanks for the replies.

tjm73

· #8 · Oct 18, 2020

A 351W put together with a decent set of heads, a good intake and well matched cam should put out 400 to 425 at the crank. It would be low stress and not a high RPM screamer. Any moderately well matched engine, IMO, should make an easy 1.2-1.25hp/CID on pump gas.

Goinbroke2

Discussion Starter · #9 · Oct 18, 2020

Yeah, this will be a stock 351 with a 4bbl and headers, I’m switching to 3.55 gears. This will be a “for now” engine. I’ll drop in the 460 after a season or two unless this really impresses me. Then I might pull it apart and build it for power. My cut offs are 13.5 and then 11.5 so I need 275-300hp and then 4-450hp. I saw used aluminum Windsor heads locally for $1300 just to give you an idea how isolated I am, lol. So 460 with minimal work will give me 400hp and only turn 5500.

Mark O'Neal

· #10 · Oct 18, 2020

tjm73 said:
A 351W put together with a decent set of heads, a good intake and well matched cam should put out 400 to 425 at the crank. It would be low stress and not a high RPM screamer. Any moderately well matched engine, IMO, should make an easy 1.2-1.25hp/CID on pump gas.

How do you keep the power that low?

Reactions: 2

Mark O'Neal

· #11 · Oct 18, 2020

Goinbroke2 said:
First post here, just getting into 351w’s.
So, my bracket car (83 mustang gt) got laid up after blowing the 3rd engine in 4 years, having my first kid and buying a new house. It’s only been 22 years! I’ve raced everything from escorts to f150’s to 8.90 roadsters over the years. Just retired in July and the kids are gone, I’m getting the gt back out. Have a 460/c6 combo I was going to put in but decided to stick to sportsman for the first year or two.(13.5-20 et) I am NOT running another 8000rpm small block...ever! Want a 5500rpm big block ....but, in the meantime am looking at a 351w/p heads I have as well as a .512/[email protected] cam I have.
So, junkyard 351 with 750dp I have and 1 3/4 long tubes with aforementioned heads/ cam. Guessing 300 hp, that puts me at 110mph and with my 4.86’s, about 6400.
Wild guess, but would the stock bottom end hold that? I’m guessing no but would like a second opinion. It has a 9” out of a 76 bronco and I have a set of 3.50 gears too.
I’m thinking that cam won’t wind the 351 up(still making power) past 6000 so maybe go 3.50’s anyway. How’s that for a first post? Lol!

What rpm will a stock Windsor handle.(repeatedly)

6,400 rpm would be fine.

Cam is too small. Look at a ProMaxx Shocker head if you're on a budget. That head, with a .575ish_235/245ish @ 50 112 LS cam with 10.5:1 compression will make about 575 hp...and you can drive it to 7-11 any time you want.

tjm73

· #12 · Oct 18, 2020

Mark O'Neal said:
How do you keep the power that low?

I say it should make that as a base minimum it should be able to put out with everything being on the "small side". If a 351W with ANY aluminum head, 9:1ish, a halfway decent cam and intake with a 750 had better make 425ish hp.

408foureye

· #13 · Oct 18, 2020

FWIW, my 351w didn't show any signs of cap walk running it up to 6700 regularly. That was with ARP main studs and 28 oz crank.

Reactions: 1

Goinbroke2

Discussion Starter · #14 · Oct 18, 2020 (Edited)

Mark, I have a roller cam that I can’t identify, found it out back. It’s .579/.589 or whatever so that would be a [email protected] cam, but that would make too much power(and at too high rpm) I only need 275-300hp max, my concern with rpm was the fact I’m running 4.86’s. Certainly get out of the hole, but would be floating along the back 1/8th Reving but not pulling. Since I’ve decided to switch to 3.50(or 3.55 if I stick the 8.8 back in) this will be low rpm torque engine. If the stock cam noses over around 4600 I’ll probably shift at 45-5000. So, stock cam/heads with 4bbl and headers. 250hp at 4600 will make a good 13.5 et engine. Edit: just checked, 250hp at 3000lbs is 13.3 at 101mph. Run at the top of the class and always be chaser. Now reality and computer programs are different so I’m guessing 13.5-13.7 at 100 or so.

tjm73

· #15 · Oct 18, 2020

I ran 99-100 every single run in an otherwise bone stock 90 GT convertible with 1.72 rockers and a B303 and full exhaust 25 years ago. 2.0-2.1x 60 foots. Suspension and practice would net the times you are talking about. Car was very consistent.

Suspension was 275/50 drag radials, a pinion snubber and 3.73's. OEM T5, Steeda Triax shifter.

Miss that in some ways. Simple. Reliable. Sounded good.

Goinbroke2

Discussion Starter · #16 · Oct 18, 2020

Tjm, that’s how it started, then I went bigger, better, faster and ended up with 1.94/1.5 chev valves in the d8 heads fully done( before aftermarket heads) stupid big cam and f28 2x4 intake with a pair of 625 comp series carbs. I was running low, low 12’s when local bbc chevelles were the running the same. I was running 7500-8000 with 289 rods and arp bolts and spewing valvetrain once a year because I was young and dumb. The go faster mindset took over from the “you’re just bracket racing, be smart”. After popping the hood and seeing the damper pointing at the ground for the last time, I swore I would never run a 302 again. 351 was not the plan either but 4500-5000, it better last! Lol.

Mark O'Neal

· #17 · Oct 19, 2020

Goinbroke2 said:
Mark, I have a roller cam that I can’t identify, found it out back. It’s .579/.589 or whatever so that would be a [email protected] cam, but that would make too much power(and at too high rpm) I only need 275-300hp max, my concern with rpm was the fact I’m running 4.86’s. Certainly get out of the hole, but would be floating along the back 1/8th Reving but not pulling. Since I’ve decided to switch to 3.50(or 3.55 if I stick the 8.8 back in) this will be low rpm torque engine. If the stock cam noses over around 4600 I’ll probably shift at 45-5000. So, stock cam/heads with 4bbl and headers. 250hp at 4600 will make a good 13.5 et engine. Edit: just checked, 250hp at 3000lbs is 13.3 at 101mph. Run at the top of the class and always be chaser. Now reality and computer programs are different so I’m guessing 13.5-13.7 at 100 or so.

We never ran them over 6,200.....which was the reason we kept the LS at 112. It was our pretty much standard grocery getter combination.

But I get what you're doing.

Reactions: 1

Goinbroke2

Discussion Starter · #18 · Oct 20, 2020

Well, it got dropped off last night. Started pulling crap off... Ford makes me wonder sometimes. Pull the upper intake, got 5 bolts out...wtf is this? I have the right torx socket but I can’t get a socket down between the tubes? Since I dint need any of it, mister pry bar was employed. Good thing I am going carb, but what Kind of socket do you use to do it properly? One exh stud broke off too but it’s sticking an inch or two out of the head, I’ll go at that tomorrow.

Yippee, my first Windsor! Lol.

pkstang

· #19 · Oct 21, 2020

tjm73 said:
My brother has a 418W in a stock block that sees 7000rpm every single time he drives it. Last time it was apart for refresh/rebuild (mo powah!!) it had only the slightest evidence of cap walk. Nothing to even get concerned about.

forged crank i take?

Mark O'Neal

· #20 · Oct 22, 2020

We did it with cast cranks for decades.

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