351 to 427

427supr · #1 (**permalink**) 11-23-2007, 06:22 AM

I've got one of the older SPF cobra's, #046. I've been running a SVO 351 for almost ten years. It's quick, but I think it time to pull it and stroke it to the 427 cubes. I am hoping after I am done, I will get that big block/torque feel. I know this subject has been covered many times. I would appreciate any feedback of the difference in running a 351 and than going the 427 stroker route in performance.

RACER X #99 · #2 (**permalink**) 11-23-2007, 07:49 AM

Go for the extra bucks and get an aftermarket block, World Products or Dart. Stud girdles on 2 bolt blocks are just band aids. Get the 4 bolt mains and the larger bore that the aftermarket blocks allow. No point in putting a $500 block in a $50K car. Do it right, now that you have decided to go big cubes.

Tony Losiniecki · #3 (**permalink**) 11-23-2007, 08:09 AM

I second Race X's suggestion. I jumped the gun and purchased a stroker kit for my 351 W block. After the fact I was told from Ford Motorsports that you should not stroke the Ford block over 4". There are all kinds of stroker kits out there and most of them use a 4.170 stroke. They do work but why take a chance. Spend the extra $$ and get a good block that will allow a 4.125" bore and a 4" stroke, this should give you the 427 your after. The Dart block will have the 4 bolt main and much better oiling. I am pushing my 351W block aside and going the Dart route. Live and learn.....

TerrysSPF · #4 (**permalink**) 11-23-2007, 09:43 AM

I agree with all of the above. Spend the extra $$$ and get a better block if you want to take it to 427 cubes. Or, if you don't want to get a new block you could always stroke yours to 392 or 408.
I always put a good word in for these guys when someone is talking about stroker kits. They're shop is near me (but they will ship) and I know a lot of people that have used them and are very happy with their products & service. www.dssracing.com

427supr · #5 (**permalink**) 11-23-2007, 10:11 AM

I really don"t want to pay the extra $2,500 for a new block. I can look into stroking it to 408, but I will probably take a chance on my Ford Motosport block and stroke it to 427. I primarily drive the car on the street, without hammering it to often.

SPF1061 · #6 (**permalink**) 11-23-2007, 10:45 AM

The Sprotsman block will not reliably support 427 cubic inches.
There's a reason all of the engine builders that warranty their product use an aftermarket block for the 427 stroker.
But, hey, it's your time and money. Spend 'em any way you like.

carbon777 · #7 (**permalink**) 11-23-2007, 10:52 AM

A stock block will be fine for street use but lots of track time or over 600 hp you may split the webs. True a Dart block will give you extra insurance but even with a Dart block other things can go wrong....nothing lives forever!

One thing I will say is there is special machine work that needs to take place to clearence the block for 4.170 stroke plus you need to use a small base circle cam to keep from hitting. Your machine work on your block could run ~$600 - $700 dollars. Now if you go with a Dart block and the "same" bore and stroke you will need to machine it too. However most go with less stroke and more bore to get the rod ratio better closer to 1.54 and avoid that extra machine work.

The other thing that kills stock blocks is RPM ......keep it under 6K and it will live much longer.

I currently have a 427w.

Hope it helps.

Jim Kellogg · #8 (**permalink**) 11-23-2007, 11:12 AM

Back to part of his original question...
(I am thinking of upgrading also. I have driven almost 35,000 miles on my SPF with a Ford Motorsports 351/385 with 3.27 diff and 5speed)

Anyone that has moved from 351w (380-400hp) to 427w (500+hp) and want to share the experience? Did the extra hp make a big difference in actual performance (say up to 100mph). Traction is a bit of an issue now, so I would think that would limit the actual performance gain of the 100hp or so...

No doubt there would be a big performance gain above 100mph.

How about some "seat of the pants feel" and actual numbers from those here who have upgraded their cars?

thanks in advance,
Jim

RACER X #99 · #9 (**permalink**) 11-23-2007, 02:30 PM

Quote:

Originally Posted by Jim Kellogg

Back to part of his original question...
(I am thinking of upgrading also. I have driven almost 35,000 miles on my SPF with a Ford Motorsports 351/385 with 3.27 diff and 5speed)

Anyone that has moved from 351w (380-400hp) to 427w (500+hp) and want to share the experience? Did the extra hp make a big difference in actual performance (say up to 100mph). Traction is a bit of an issue now, so I would think that would limit the actual performance gain of the 100hp or so...

No doubt there would be a big performance gain above 100mph.

How about some "seat of the pants feel" and actual numbers from those here who have upgraded their cars?

thanks in advance,
Jim

Jim, I went from a 427FE to a 351 385 HP Ford crate engine. Handled better, no noticable performance difference.
Then from the 385 HP to a 408 CI Dart 600+ hp (leaded race gas)...big difference especially on the track with open headers and slicks. could pass almost everybody with ease.
I had the misfortune to drop a valve in the 408 and was forced to overbore to 4.125 and now I have a 427. I also detuned with less compression,a smaller cam and unported heads.... picked up bottom end torque but lost some top end power. I have not been on the dyno with this combo but based and seat of the pants feel I am guessing around 500HP ( I can now run pump gas but still use 100octane on the track)

You will notice the power over 100MPH

385 HP = run with the stock FE's
600HP= run past the FE's and just about everybody else.
500HP= run with most everybody on the track pass most on the street.

The one thing I have learned is that race engines belong in race cars and a fun track car does not need a race engine.

carbon777 · #10 (**permalink**) 11-23-2007, 11:27 AM

Couldn't say never ran a 351 .....went right to 427w

TerrysSPF · #11 (**permalink**) 11-23-2007, 10:48 AM

As they say................pay now, or pay (much more) later.

-Good luck!

bobcowan · #12 (**permalink**) 11-23-2007, 11:57 AM

I used a 427W with a stock block for a while. 4.060 bore x 4.125 stroke. Cast crank, stock Chrysler rods, hypereutectic pistons. It ran good, and I beat the hell out of it. Ran it on the road course for hundreds of laps. I finally spun a rod bearing because of an oiling issue.

Now I have a Dart based 427, 4.125 bore x 4.000 stroke. Why did I upgrade? Because I plan on beating on the engine even harder over the next couple of years. I wanted to make sure it would last. The Dart block has better oiling, and smaller mains for higher rpm's.

But, the point is, I see nothing wrong with a stock block 427. Companies like Coast High and Keith Craft sell hundreds of them every year. It has some limitations. As long as you understand those limitations, you'll be fine.

Tony Radford · #13 (**permalink**) 11-23-2007, 04:03 PM

My car came with a stock stroke 351, hydraulic performance cam and sufficient performance parts to get around 400 HP. I traded the engine back to the builder for a 427W stroker. He used the same heads, but the intake, carb and cam (solid flat tappet) were upgraded. The rotating assembly is Scat for the crank and rods and Keith Black for pistons. My billet steel flywheel was replaced with an aluminum one and the rockers are now Erson rollers. The TFS heads were ported and matched to the Vic Jr. intake. The block is a stock Windsor block. Performance difference is night and day. I've run it up to around 6,600 RPMs and it pulls strong with no sign of rolling off. So to answer the original question, yes (assuming the stroker is configured right and well built with quality parts), you'll have a rocket sled. Bill Parham (Southern Automotive) designed my stroker and had no reservation about putting it in a stock block.

Dwight · #14 (**permalink**) 11-23-2007, 07:28 PM

408
408
408
408
408

SPF1061 · #15 (**permalink**) 11-23-2007, 08:45 PM

Quote:

Originally Posted by Dwight

408
408
408
408
408

Tony Losiniecki · #16 (**permalink**) 11-24-2007, 09:08 AM

OK, so we know that a lot of the guys are running stroked 351W blocks. We know its safe to go to a 408 (keeping the stroke under 4") Knowing that you have a budget (we all do) I would think the best options is to purchase a good 408 Stroker kit. Get a good kit that uses good parts. You wont be disappointed... I personally met a guy with a 351W stroked to 427. This short block was pro built. The guy didnt beat on the car but after about 2 years (summer use only) one of the pistons pushed a hole through the side of the block. He suspects this is from the heavy side load from the 4.170 stroke.
This is the reason that I decided to keep the stroke under 4" (personal preference).

427supr · #17 (**permalink**) 11-26-2007, 07:38 AM

I got on the stroker heaven website. They have a 351/434 stroker kit using a Scat crank with a 4.000 stroke. Seems it would be safe to put this kit in my stock SVO block, being that it is at the 4.000.

www.strokerheaven.com

Tony Losiniecki · #18 (**permalink**) 11-26-2007, 03:15 PM

Wow, thats a lot of CI from a 351. You may want to check out the required bore for that monster. I guess you would also want to check the max allowable bore for your block. Would you be pushing your block to its max bore with this kit????

SPF1061 · #19 (**permalink**) 11-26-2007, 08:45 PM

Quote:

Originally Posted by 427supr

I got on the stroker heaven website. They have a 351/434 stroker kit using a Scat crank with a 4.000 stroke. Seems it would be safe to put this kit in my stock SVO block, being that it is at the 4.000.

www.strokerheaven.com

I just took a look at this site. Here's a quote from the first page under the section:
"IMPORTANT INFORMATION! PLEASE READ!"
>>Some large Ford stroker engine kits (& other brands) may require stroker pans and the use of a aftermarket block. <<

TerrysSPF · #20 (**permalink**) 11-26-2007, 08:55 PM

Quote:

Originally Posted by SPF1061

I just took a look at this site. Here's a quote from the first page under the section:
"IMPORTANT INFORMATION! PLEASE READ!"
>>Some large Ford stroker engine kits (& other brands) may require stroker pans and the use of a aftermarket block. <<

Ssshhhhh. Not so loud, SPF1061! We all new he couldn't do it with his block, but I for one, am going to wait with a big smile on my face for his next post a few weeks from now titled: "Why did my 427w blow up?"