302/347 vs. 351w/408w

[smoktf250]

Hey guys I have been having a difficult time deciding what motor to put in the bronco...I want a stroker motor...either a 302 stroked to a 347 or a 351w stroked to a 408w. The bronco is mostly a street bronco...I want some get up and go. ;D

 

[Madgyver]

The bigger the better as long as your pocket can handle the costs of gas nowadays....

Don't even think about the 302/347 idea because when you are done with it you'll tell yourself, "I should of just dropped in a 351W"

For a street truck save your money and put in nasty built 351W, Tell everyone it's a 408 stroker... No one will know the difference but yourself.....


Any great engine builder can get away with that one.....

 

[mr incredible]

I HAVE A 347 .. and i gotta side with mad ,, i shoulda done the 351 ,,,,
it is ok ,, and has good power ,, but i dunno if it will ever match a 351 ,,,,

 

[bax]

I have a 408 and I should of done the 434.

 

[smoktf250]

How are your guys trannys holding up? Are you guys running c4's? If so what have you done to your c4...to withstand the horsepower.

 

[av8rds]

I have the 393 with the bore is about 396(if I remember right, its been awhile)
I'd go bigger if I were to do it again.

After seeing that others are getting about the same TQ at only a few hunderd rpms higher than mine and a lot more HP I'd also use a higher RPM cam. Right now my engine dies off at 4500rpm. I got exactly what I asked for from the builder at the time but looking back with my gearing and what not I could/would put in a 'bigger' cam.

you can see the dyno sheet attached. We only printed one of the runs but you can see I made a handwritten note on it that even at 2100rpms it was making 450lb-ft of TQ

 

[smoktf250]

I was thinking of building a 408 with these parts...whats your guys opinion

Edelbrock Victor 7721 aluminum heads With valves and header plates.
Probe Shaft mount 1.6 rocker arms
Probe flat top .040 forged pistons with childs and alberts h11 pins and rings
Eagle forged 6.2 h-beam rods with bearings
Eagle forged 4.0" stroke crank
Rollmaster double roller timing chain
Romac 50 oz balancer
1974 351w Block

 

[Broncobowsher]

I have a stroked 302 engine with a cam in my Ranger.
I have a non-stroked but long rod 351 in the Bronco.
On the chassis dyno the peak HP between the engines is nearly the same.
The 351 gets better mileage and is more fun to drive. This morning I started pulling the stroked 5.0 engine out to fix an oil leak and put a smaller cam in it.

From what I have played with I will recomend doing a 351 based engine. I like long rods, the longer the better, just stay out of the oil rings if possible. Go with a smaller cam then ideal. just off idle through 5500 is a great window to shoot for. Also remember that big inches tend to tame down big cams just a little. I run the exact same cam in my 351 as a friend does in a 302 mustang. The extra 50 cubic inches tame down the idle a little and has a little better bottom end power. Top end power is nearly the same.

As for stroker kits, I spent a lot of time researching it. Went to SEMA and talked wih Scat, Eagle and others. I liked Eagles complete kits. Flexplate to balancer, prebalanced at the factory. Don't have to worry about the correct wristpin diameter to order or what rod bearings to use. The crank is machined to the right width for the rods. There are a lot of potential problems when mixing and matching parts to make a stroker. Make one oversight and you have some pricy parts sitting n the garage that don't work together. I was also very impressed with Eagle when I gave them my plans and what I was thinking about. They kindly pointed out that going from forged to cast crank will be more then enough for my plans and going from H to I beam rods will save recricapting weight.

Unfortunatly I was not as impressed with Scat when trying to get recomendations out of them. There favorite line was "what we learn on our high dollar cranks we bring to our entry cranks". That was after asking why I should choose there kit over there compitation. That was a basic "I don't know and let me gloss over your question with some impressive side stepping".

As for the above combonation, I see problems. Victor heads are small cc heads. I can't find 7721 heads, all the part numbers in the Edelbrock catalog for heads have 5 digits to them. But the few I did see were in the 60cc range. Then you are listing flat top pistons. To that I will ask which diesel injectors are you planning on running? because with that much compression you are looking at some insane compression ratios, 13:1 comes to mind. I have a calculator but it isn't on this computer.

 

[smoktf250]

It is this cylinder head
77219
Victor Ford

Designed for ultra high-performance and large displacement small-block Fords (high rpm 302s to 351 and larger Windsors)
Extended intake flange works with Victor Series manifolds using end-seal spacers #7726
240cc intake ports are raised .375" and measure 2.10" tall by 1.16" wide as-cast

VICTOR FORD
Chamber Size Intake Port Size Valve Sizes (in/ex) Bare (single) Complete (single)
47cc 240cc 2.125"/1.625"(B) #77219* N/A
End Seal Spacers (1 pair, required for Victor Ford cylinder heads) #7726

 

[73stallion]

next engine i build will be a 331 stroker. a friend of mine has one cranking 355.8 horse at 5,100, 396.6 torque at 3,000. that'd be just enough i think.

 

[fordguy]

l like the 331 but with a stock block it comes out to be a 327 hence you can tell people you have a 327. But i would def go with the 351 cause nothing replaces cubes for me. Bowsher, I dont see the rotating assembly for the crank part number 103513850 (uses the stock 351 rods and 302 pistons). I have read the 408 arguement but i am going to build a budget storker. I traded for a really nice marine 351 block. I dont see any fitment problems with this setup. the 408 would be great if you have the bucks.

 

[Broncobowsher]

47cc chambers, flat tops. Thats about 15:1 compression. I know diesels with a lower compression ratio then that. What were you planning on fueling this with? Even with 28cc dished pistons (biggest dish I could find in a minute of looking) you are still looking at over 11:1 compression.

Unless you are planning on fueling this with CNG I strongly recomend researching another head with a much larger chamber size.

As for the budget concius, I usually spend too much. I have not used a set of stock rods since the '90s. My 351 uses 6.120" Ford motorsports powered metal rods (don't bother looking for them, they were never in the catalog and only had one ad ever). The 5.0 is actually a 330" 3.250 stroker with a .020 overbore with 5.4" new style Eagle H-beam rods. New style is cap bolts instead of bolt and nut. And countless friends Chevy stuff and never a stock rod in sight. Next engine probably won't even be a stock block but that is years away.

 

[av8rds]

Next engine probably won't even be a stock block but that is years away.

oh yeah cant you get like 470ci out of an aftermarket block..the name escapes me right now..but I remember reading about it, and it was 'fairly' reasonably priced.

 

[fordguy]

a stock block (standard bore 4.00) with a 3.250 stroke will give you 326.7264 cubic inches hence a 327

 

[av8rds]

sorry way off the original topic:

http://www.worldcastings.com/prods_pages/add_info/087110_001_more.htm

I was off...460ci

 

[SnwMnkys]

I was thinking of building a 408 with these parts...whats your guys opinion

Edelbrock Victor 7721 aluminum heads With valves and header plates.
Probe Shaft mount 1.6 rocker arms
Probe flat top .040 forged pistons with childs and alberts h11 pins and rings
Eagle forged 6.2 h-beam rods with bearings
Eagle forged 4.0" stroke crank
Rollmaster double roller timing chain
Romac 50 oz balancer
1974 351w Block

Whats with all the forged parts? Are you running forced induction or spinning the piss out of the motor? Is it a sand drag, or mod bogging truck?

If not then save some money and ditch that forged crank and buy a good cast peice, and those rods arent really nessecary if your not going to rev the motor past 6k. There are plenty of cheaper I beam rods that will handle 500+ HP. If you are not going to be running forced induction or nitrous then a good hyperuetectic cast piston will work fine.

Like i said, it depends on what you are doing with the motor, but those heads are probably a little big, even for a 408w if you are just going to use it for some off roading and street driving. The RPMs would probably be a better choice. What kind of cam are you going to be running?

 

[feitctaj]

a 460 Clevor gives me wood

 

[smoktf250]

Here are a few more questions for you guys.

So what would be the best built 408? How would you guys build it...??? I want around 500+ hp. I want my bronco to be running high 12's-13 in the 1/4 at 5500ft elevation with 35" tires. Think I can build this motor for $5K? Also can a c4 handle the horsepower? What tranny would you guys go with?

 

[Broncobowsher]

10~10.5:1 compression would be a good starting point. That should run good at altitude.
Heads could be argued forever. I would recommend a 2.02/1.60 head. Those huge valves probably have flow issues when run on a standard 4” bore engine. Now if you were running an aftermarket block with 4.125” bore then they wouldn’t shroud the valves so much.

500 HP is your only goal? Do you want any low end power, street driving, economy? An engine that makes 500 HP is fairly easy with a nice big cam and carb. The ability to enjoy it anyplace other then high RPM on the dragstrip is another issue.

 

[DonsBolt]

Here are a few more questions for you guys.

So what would be the best built 408? How would you guys build it...??? I want around 500+ hp. I want my bronco to be running high 12's-13 in the 1/4 at 5500ft elevation with 35" tires. Think I can build this motor for $5K? Also can a c4 handle the horsepower? What tranny would you guys go with?

If you really want to take it to the drag strip, and run high 12's at that altitude, there is a lot more than just HP.

I took my bronco to the drag strip this fall, (sea level) 302, 35 inch tires, 456 gears, 50 lbs of tools, high lift jack, spare tire, a good 25 gallons of fuel I ran a 15.2, but bogged a little off the line. I know with a little tunning to my carb it has 14's in it.

With the short wheelbace of a bronco, you want to keep the suspension lift as small as possible. Enen with my 340 Hp the weight transfer with my 3.5 inch lift, was pretty extreem. My rear end really squated down, and the front end lifted pretty high. While those are both good things, the soft springs all the venders sell these days are not good for a drag racing setup. You will need a good set of traction bars, and some springs that will somewhat control the way the truck launches. Also 35 inch tires and wheels are heavy, and take a lot of power to get going. If you can limit your tire size to 33 inch, and keep the lift around 2.5 inches, that will help you at the track.

As far as transmissions, a properlly built C4 can handle your power, but you would be better served to run a modern trans that you can put a high stall converter in. Maybee something like a Explore trans, or a GM trans. Trust me you can spend as much for a transmission/converter as you are planning to spend on building a motor. Most standard transmisions that can handle 500 HP are not geared right for drag racing, so I would stick with a automatic, with a 1800-2400 stall converter.

If you just want a fast truck, and don't plan to go to the track, than in all means go for 35's with a taller lift.