351 to 427

[427supr]

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]

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]

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]

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]

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]

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.

[TerrysSPF]

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

-Good luck!

[carbon777]

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]

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

[carbon777]

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

[bobcowan]

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.

[RACER X #99]

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.

[SPF1061]

Jim -
I put @ 32,000 miles on a FMS 392/475(?)hp. Replaced it with a Roush 427R/550hp which now has about 14,000 miles on it. With the FMS I was constantly doing upgrades trying to get a little more power. Pro Systems carb, Trick Flow heads... With the Roush I had an AED carb custom built and dynoed for the motor to replace the POS vacuum advance 870 that Roush shipped on the engine. I made that change as soon as I got the motor because I hated the vaccum secondary throttle response. I have not felt the need to make a single change to this motor since then. I have felt the need to put BIGGER BRAKES on the car!!!!
There is a huge difference between the 392 and the 427, both seat of the pants and measurable. The 392 as it came from Ford would run low 12 sec 1/4 mile.
After all of the upgrades I did to it I was running 11:70s. The 427 currently is running 11:30s. I think that when I get my launch perfected I will get into the 11:20s. In short, there is a HUGE difference between the FMS392 and a Roush427R. Hope this helps. Let me know if you have any specific questions.

[Tony Radford]

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]

408
408
408
408
408

[TerrysSPF]

427supr: Hey, everyone has a story - some good and some bad from over-boring a stock block. -I'm just going by what most builders I know "recommended" to me when I was looking at smallblocks a few years ago. Sure, I thought it would be nice to be able to say I had a "427" under the hood, but as soon as you open it, it's easy to see it's not an FE.
I'm just saying, why take the chance when you can get 500+hp out of a 408?

[SPF1061]

Originally Posted by Dwight

408
408
408
408
408

[CHANMADD]

For high RPM, HP longevity you need the rod ratio to be 1.6 or better , which depends on your driving style. If you like to Rev your motor ,like I do an undersquare motor with good Rod ratio is niceeeee!!!!

[Rick Parker]

Two words............Rod Angle!

[Dwight]

TerrySPF is telling it like it is. Keith Craft can build you a 408 street motor with 535 hp for "about" $9000 + -.
If you want a fast street car then the 408 is a great choice. If you want to say 427 then you need a FE.


Dwight


I tried to post a pic of KC 408 but the gallery says I'm over quota. I removed about 10 pics but it will not let me upload more.
The motor is a thing of beauty.
Call Keith!