Mild 351 or 408 Stroker

[SSDDBRONCO]

Ok im on the fence if I should get a built mild 351 roller with stock bottom end and aftermarket heads and cam?

Or if I should just go big and get a 408 stroker?

Both will definitely be a big improvement over my 302, just trying to get input from guy that have experience running a mild 351 and/or 408. Is it really that necessary to have a 408 or will a 351 be plenty? Also other concerns are overheating issues and if I'll start breaking shit left and right lol.

A little info about my Bronco. I have a 4r70w running 4.88 gears and 35's, and Holley Terminator EFI.

Thanks
Kev

 

[jmhend]

Ok im on the fence if I should get a built mild 351 roller with stock bottom end and aftermarket heads and cam?



Or if I should just go big and get a 408 stroker?



Both will definitely be a big improvement over my 302, just trying to get input from guy that have experience running a mild 351 and/or 408. Is it really that necessary to have a 408 or will a 351 be plenty? Also other concerns are overheating issues and if I'll start breaking shit left and right lol.



A little info about my Bronco. I have a 4r70w running 4.88 gears and 35's, and Holley Terminator EFI.



Thanks

Kev

Tell us more... what do you want or think you want out of the broncos power plant? Low end torque for the rocks / sand? High ram? Good gas mileage? Lol

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[SSDDBRONCO]

Definitely low end torque. Want it to be capable to handle whatever I through at it. Mud, sand, rocks (not too extreme rock crawling) but then be able to take a nice cruise down to the beach or the grocery store in another city haha. Meanwhile we all know gas mileage isnt the greatest with our Bronco I would still like it to be decent. Not looking for something that will be getting 8 mpg lol. If i can manage to get 12+ mpg I'll be satisfied with that.

Tell us more... what do you want or think you want out of the broncos power plant? Low end torque for the rocks / sand? High ram? Good gas mileage? Lol

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[jmhend]

Definitely low end torque. Want it to be capable to handle whatever I through at it. Mud, sand, rocks (not too extreme rock crawling) but then be able to take a nice cruise down to the beach or the grocery store in another city haha. Meanwhile we all know gas mileage isnt the greatest with our Bronco I would still like it to be decent. Not looking for something that will be getting 8 mpg lol. If i can manage to get 12+ mpg I'll be satisfied with that.

Then my vote would be rebuild the 351 (I hope its a roller) put a good low end cam in with aluminum heads and run it.

Good luck with your decision.

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[SSDDBRONCO]

Then my vote would be rebuild the 351 (I hope its a roller) put a good low end cam in with aluminum heads and run it.

Good luck with your decision.

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Care to elaborate why? Just want to know you would go that route. And ya I'm telling the engine builder I want a roller block.

 

[Madgyver]

Go big! 408W........

 

[Broncobowsher]

408

You can have more fun with a less stressed motor. With enough cubes, it just makes power everywhere.

Once you open the core 351 and look at the crank, it might just make the decision for you. Getting a crank ground, rods reworked, new pistons installed... How much is that pre-balanced stroker kit again?

 

[SSDDBRONCO]

@Madgyver and @Broncohowsher… y'all ain't having any over heating issues with your 408?

 

[Madgyver]

@Madgyver and @BroncohowsherÂ… y'all ain't having any over heating issues with your 408?

Taz had a stuck lifter issue that we replaced last night. 32* total timing and she runs cool.. maybe too cool 180* cruising... Inner fenders are vented. push spal 17" eletric fan in front radiator, explorer front dress with clutch fan. crappy aluminum champion radiator. I say crappy because I've gone through too many of them over the years..

 

[73azbronco]

Taz had a stuck lifter issue that we replaced last night. 32* total timing and she runs cool.. maybe too cool 180* cruising... Inner fenders are vented. push spal 17" eletric fan in front radiator, explorer front dress with clutch fan. crappy aluminum champion radiator. I say crappy because I've gone through too many of them over the years..

Take the electric fan off, buy a stock copper bronco radiator, ensure you have the metal fan with HD clutch working with the explorer serp stuff, and shroud from WH. It will keep you cool.

And nice motor, only small regret I have is not going 408 when I decided 347

 

[Rustytruck]

Mad,
nice work, do you deal with emissions out there in old Broncos? Cooling in Hawaii with 30 percent humidity shouldn't be too hard. with oversize engine you don't work them too hard to create all the heat. If rethinking all involved cost and drive-ability would you do it again? especially fuel costs. you have unique situations living on a small island.

 

[Madgyver]

Take the electric fan off, buy a stock copper bronco radiator, ensure you have the metal fan with HD clutch working with the explorer serp stuff, and shroud from WH. It will keep you cool.

And nice motor, only small regret I have is not going 408 when I decided 347

we may install a switch for the fan. This is the last of the aluminum radiators I have in stock. Next in line is a copper core new in box. Motor runs cool..

I have a built 347 for the green77 and a 393C for my yellow77. For now the 351W is doing fine but swap will come soon.

 

[Madgyver]

Mad,
nice work, do you deal with emissions out there in old Broncos? Cooling in Hawaii with 30 percent humidity shouldn't be too hard. with oversize engine you don't work them too hard to create all the heat. If rethinking all involved cost and drive-ability would you do it again? especially fuel costs. you have unique situations living on a small island.

Lucky we don't have smog test here but we do deal with a vehicle reconstruction permit (locals call it "recon").
I'm itching to build another 408W as I have a block at the machine shop to pick up. My attitude is you can do it now or regret it later. Covid has done so much displeasure here in the islands most of the trails are blocked off and so are the coast lines. Favorite fishing spots are not easily accessible now. No drive in access, gotto hike in... it sucks.
Drive 100 miles and you gone around the island...

I do love the low end grunt that the 408 provides. Build it with Eddy Vic Jr heads, an Eddy dual plane air gap intake and a Rochester Qjet. Made it fit no body lift.

 

[Rustytruck]

Mad,
I cant Imagine what the people that who are not in government are going through out there. Here in the Communist republic of California the powers at be kneeling on our necks is tough enough, but raw material supply issues are really hampering manufacturing and soon the general public is going to find out how tough life and recovery is going to be. I love the islands, best wishes for you all.

 

[snipes243]

I'd go 408w I currently run a 393w and its a beast. With the right radiators and fan they can run nice and cool. We just done with a 2 week adventure through cali, Utah, and Colorado. Put over 1300 miles between trails and drive to the trails and the motor never went over 196 degrees.

 

[jmhend]

Care to elaborate why? Just want to know you would go that route. And ya I'm telling the engine builder I want a roller block.

Sorry for my delay. I personally put things in the perspective of cost / vs reward.. for example why buy a Lamborghini or Ferrari when you only drive it 10 miles to work through a neighborhood with a 25 mph school zone... i know that is an exaggeration but I think it applies.

Why build and spend the money on machining a 408 when you will never use it or the horsepower gain is so trivial that it doesn't make sense unless you just want to say that you have a 408.

My .02 I try to put the money where it is needed. I love these other guys but for mr you can build a similar 351 for less and be just as happy. I well with a guy that has a 351 and he loves it. NEVER has he said man I need more.

Good luck either way.


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[nvrstuk]

jmhend... I am not a believer in how one would never need or use the a 408's power over a 351w- - EVER actually.

I've built & spec'd strokers for friends and myself since the '90's for Broncos. Not ONE of the guys have ever regretted the availability of power, not one.

I can show many examples of when a 408's power can not only get you out of potential trouble but allow you to go places you can't with a 351W. How can I say this? Because I've built and driven Broncos with 351W's (my own 351W for 15 yrs and my own 418 and 460 for 11yrs) and built and driven Broncos with 408's, 418's, 427's, 454's and 460's. I can easily show how the strokers develop the torque and HP needed in deep sand, sand dunes, mud, & deep wet snow to go where you can't with a 351W. Mud and sand literally suck HP.

The 408 costs an insignficant amount more than the 351 as strokers have become so commonplace the last 15 yrs- everybody's got one (almost).

Cooling is not an issue at all with aftermarket blocks. Like none at all.

351W blocks need to have everything working efficiently to cool them when subjected to heavy sustained loads. Not talking just wandering about but when making serious power a big stroker generates a lot of heat because they are burning a lot of fuel.

MPG- my 418 when checked accurately for mileage could get 12mpg with 40's when cruising at 55mph for 100+ mile trips, filled up at the same location, same pump, odometer is checked and accurate to 1%.

Hope this helps.

 

[Madgyver]

It's just because "I" built it.... My reasoning...

 

[jmhend]

jmhend... I am not a believer in how one would never need or use the a 408's power over a 351w- - EVER actually.

I've built & spec'd strokers for friends and myself since the '90's for Broncos. Not ONE of the guys have ever regretted the availability of power, not one.

I can show many examples of when a 408's power can not only get you out of potential trouble but allow you to go places you can't with a 351W. How can I say this? Because I've built and driven Broncos with 351W's (my own 351W for 15 yrs and my own 418 and 460 for 11yrs) and built and driven Broncos with 408's, 418's, 427's, 454's and 460's. I can easily show how the strokers develop the torque and HP needed in deep sand, sand dunes, mud, & deep wet snow to go where you can't with a 351W. Mud and sand literally suck HP.

The 408 costs an insignficant amount more than the 351 as strokers have become so commonplace the last 15 yrs- everybody's got one (almost).

Cooling is not an issue at all with aftermarket blocks. Like none at all.

351W blocks need to have everything working efficiently to cool them when subjected to heavy sustained loads. Not talking just wandering about but when making serious power a big stroker generates a lot of heat because they are burning a lot of fuel.

MPG- my 418 when checked accurately for mileage could get 12mpg with 40's when cruising at 55mph for 100+ mile trips, filled up at the same location, same pump, odometer is checked and accurate to 1%.

Hope this helps.

Great points, certainly for the environment that you mentioned (sand, dunes, snow and mud) all of which either I don't habe on my area or I really try to avoid it.

More horsepower and never complaining is a topic that most never revisit or regret.

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[SSDDBRONCO]

Thanks for all you input guys!

I've called a few engine shops and whether I get a 351w or 408 stroker built the price is just about the same, with the stroker being a few hundreds more. I think at this point I'm leaning towards the stroker just because the price and it's a no brainer.

I think at this point I'm just afraid of breaking components on my Bronco from the torque of a 408 lol. How well do the 1310's hold up to torque from a 408?