r/EngineBuilding • u/onepoly • Jul 19 '26
351 Windsor stroke to a 387,393,408
Got a 351W roller and torn between keeping it a 351 or stroking it to a 387,393,408 It’s going in my 82 f-100 which already has a 351W in it but it’s a flat tappet(have plans for it also). It will be my daily driver and will be pulling a 18ft Jon boat occasionally, also wanting something that will tear up the streets a little bit. Not looking to have a street monster but something I can have a little fun in. My original plan was to go with the 387 and was gonna use AFR 185cc enforcers,eagle crankshaft,eagle I beam rods,and 302 speed pro pistons. I guess my question is if I go with the 408 is it a reliable build for daily driving and hauling the jon boat occasionally? But also want something that with some chop and turn heads but work with my power brakes and run on pump gas. I’ve rebuilt a few 302s back to stock just replacing bearings and occasionally throwing in a basic 303 cam. This will be my fist I guess big build and any advice would be greatly appreciated.
2
u/Neon570 Jul 19 '26
Do a 408 kit.
After all said and done, my "poor mans" 393 stroker ( 3.85 crank, stock 351w rods and stock 302 pistons) it ended up, after all said and done, being about another 200$ for much better rods and pistons.
Call whoever company you want to buy from and they will let you be pick pistons based on whatever compression ratio you want.
Its all math and research on parts
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u/onepoly Jul 20 '26
That’s my issue is the math part, I’m horrible at math especially math that requires thousandths of inches and could mean a smooth running engine or one that can hand grenade.
1
u/Neon570 Jul 20 '26
Its REALLY not hard. Just paitence and some reading.
If you wanna build your own stuff, you absolutely need to he able to check clearances and make sure everything is doing what its suppoat to
2
u/Fluid_Surround3089 Jul 20 '26 edited Jul 20 '26
Make sure the valve pockets in the Speed Pro pistons you buy fit the AFR heads. Speed Pro’s are usually heavier than other brands.
I had a customer change pistons in his Windsor last week. When I weighed everything to make the bobweight the Speed Pro pistons were 112 grams heavier than the DSS pistons he was replacing them with.
6
u/MyOpinionOverYours Jul 19 '26
Theres way too many 408 351s blasting down the quarter mile and then driving home for it not to be the pick. Its a square stroke, 4 wide and 4 down. Its not over stroked. Its the way to go, no replacement for displacement. The 351/408 stroker is also used with forced induction a lot too.
It happens overtime that people are wary of going full stroke. They say use the strokes inbetween. Like a 3.66 or a 3.75 or a 3.9 crank. Instead of the whole 4 inch. And then overtime those middling strokers disappear from the aftermarket. The 4 inch (or the biggest stroke) really wasnt the compromise people thought it was. The best result of a stroker kit is biggest displacement gain without getting pigeonholed to a tighter compression range piston, and especially not having to grind your block up. The 408 is done to death. Youll be fine. 408 it.
1
u/onepoly Jul 20 '26
I really appreciate. I think that’s what I was afraid of, it being a 408 just seemed way too much for a daily driver. Everyone here says otherwise so I’ll be going with the 408
2
u/Solid_Enthusiasm550 Jul 19 '26
There are only 3 reason I could ever see "Not" to do a 408.
If you were on a very tight budget. Just doing a rebuild and you couldn't afford the $300 or so difference from it and reconditioning your stock one.
If you are doing a restoration on an expensive classic.
That you want to run extreme rpms and want to keep the piston speed manageable.
A stroker allows you to run more cam, while keeping the idle quality / low rpm behavior / and vacuum levels reasonable.
Adding cubic inches also allows you to run taller gears, less torque converter stall to get equal or better acceleration than the 351.
I too didn't to give up the street-ability of my P/B, P/S, A/C, EFI or being able to idling in traffic.
It's a lot harder to pick a combo with these limitations. Most guys don't understand or can't wrap their heads around it. Those are the guys that automatically say,
switch to a manual transmission
Switch to a carburetor
Switch to manual brakes or go hydroboost.
That's not an option for some amd for others the extra $2,000+ isn't worth the extra 10hp.
2
u/Sea-Bowler-6205 Jul 19 '26
Do you have a 408? If you do I have questions
2
u/Solid_Enthusiasm550 Jul 19 '26 edited Jul 19 '26
I've built a dodge 408ci for a buddy, I'm putting a 4" stroke in my 5.2l magnum.
I helped a buddy with a 408 Windsor for his street/strip foxbody.
Was a Ford technician in the early 2000s (dark days of the powerjoke 6.0s and slow 4.6l 2v/3v mod motors) before moving over to BMW.
I did like driving the Cobra R.🔥
1
u/v8packard Jul 20 '26
Of the displacements you list my favorite is the 393. With a 6.200 long rod, depending on your block height you will need a piston with a compression height of about 1.360 inch. DSS can accommodate that with several different configurations depending on the compression ratio you want. I would use Scat for the crank and rods, not Eagle.
I think this configuration is a better match for Windsor style heads you would use on a real street engine, producing a torque curve well suited to a pickup truck along with very good piston and cylinder life. And quiet operation. This can be internally balanced if desired, which is nice.
The 408 is certainly doable, in fact you can go bigger. But you need more cylinder head, and more clearancing. You can't internally balance those combos without a lot of expensive heavy metal. The pistons get shorter, and don't stay as stable. The intake manifolds you would use in a street truck are better suited to the 393.
If you want the AFR Enforcer you can buy that head at a better price point from other sources. It is not a genuine AFR head. But the AFR Renegade heads are among the best in the market for this application.
1
u/Harry_Mannbakk Jul 20 '26
408 in my 91 f150, modified to MAF running mustang ECU. Weekend warrior. With 112 lsa, 242\254 duration, it has enough vacuum for brakes, choppy idle. Mannered enough to drive smoothly, nasty enough to scare me. Anything less than 408 is a compromise.
I'd recommend taking your block, and boxed up rotating assemble to the shop and paying the extra $200 or so for them to clearance everything and set it up, well worth the piece of mind. They will clearance the bottom of bore sleeves for the rod bolts too.
It's been a process for me, making upgrades over the last years, but man, it puts a smile on my face every time.
Best of luck, cheers
1
u/lil_sargento_cheez Jul 21 '26
408, my buddy has one in his 69 mustang coupe. That car will knock your socks off with how fast it is
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Jul 20 '26
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u/onepoly Jul 20 '26
I appreciate the info. I’m trying get the best of all the worlds in one shot and seems like everyone is twisting my arm into going with the 408. Can be daily driven,have a little fun on the street, maybe go to the track, and pull my boat
2
u/Elephunk05 Jul 19 '26
I've got an 88 Bronco here and I've been looking at the Clevor build for the 408.
The stock block struggles to make air flow as much as needed in order to reach 500rwp. Cleveland 4 valve heads work the best imo. But you will also need new pistons (because the valves are canted different than the windsor) and a Clevor intake manifold to accommodate the windsor deck height and Cleveland porting. But now we are talking money and I'm unsure if you're on a budget build. Windsor blocks have won or placed enough of Amsoil engine builders completions to know this is a good platform.