pro's and con's of 393, 408 and 418

2NDTIME

Founding Member
Nov 5, 2002
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Kansas City
sorry but you cant search 3 letter words. I have seen a thousand 331 vs. 347 threads. Lets get a thread about how big to go on a 351.

I am just starting to do my research and thought this might be a good way. Hopefully people will post links.
 
With a 418 you have a .040 overboar. This means you will weaken the block even farther than a 393 or 408. The 393 has a shorter stroke (3.85) than the 408/418 (4.0). THis means that there will be a more agressive rod angle.
 
So lets start with what makes each stroker combo. And what ci options there are with a stock 351 roller block. As in...

393 is a 3.85" crank. Can be had with stroker crank and 351 rods with 302 pistons. Is that std bore or .30 over?
 
Interesting thread...

With a longer stroke the piston moves more per revolution, making it move faster at the same RPM as a shorter stroke. This longer stroke reduces rod angle which puts more stress on the cylinder walls as well as energy being directed away from the crank. This reduces it's revving cabability. The longer stroke though increases tourque because it acts as a lever on a wider fulcrum.

Going back to the 331 vs 347 it is on the same principle, some like the 331 more because you can rev them better and thier rod angle is better, but the 347 usually offers more low end tq.
 
2NDTIME said:
So lets start with what makes each stroker combo. And what ci options there are with a stock 351 roller block. As in...

393 is a 3.85" crank. Can be had with stroker crank and 351 rods with 302 pistons. Is that std bore or .30 over?


393 and 408=.030" overboar
418=.040" overboar
 
Only disadvantage I see is you will probably go thru tire's very quickly...LOL

How fast do you want to go?
How much do you want to spend?
It does not make sense to build a monster moter to run 12's.
In all honesty anything less than 10's n/a
with these moters and you wasted your money. A streetable 11 second 331 or 347 is more than possible. The only advantage being the 351 parts have a better foundation to start with (block).
 
No matter what you do there is going to be advantages and disadvantages. I've always said the advantages outnumber the disadvantages so just build one.
Go 408.... check out sig..... Cruises down the highway and street's without a problem (Execpt Gas Milage) and provide's the viechle's occupant's with a violent feeling when you hit the gas.

Shon
 
FrdMustangCpe said:
dont strokers not last as long as a normal b/c its longer stroke or somethin? :shrug:

Any engine with higher compression, more rpm, stiffer valvesprings, etc, is going to wear faster than a stock 5.0. Being a stroker just means it will tend to wear certain parts faster. Throwing alot of money at the project to get really high end parts can alleviate this, but it will still happen. A superbike engine is the same way, only stock. High compression, high revving, high power, and you might get 30,000 useable miles out of it.

And thats probably why the 427W isnt mentioned much anymore. Pushing the limits of the production design there.
 
what ever you do make sure you put a BIG enough head on it!! Atleast a 225 intake runner volume, so that woud be a big high port or an AFR 225, dont wory about the old myth about loss of torque, because with such a long stroke It wont matter, and if you dont have enough head with the long stroke you'll loose 50 -100 hp!
 
I am wanting to run 10.80's or faster N/A. 3000# car and will have a C4 with a loose converter and Tbrake. Which I believe is going to take a decent 450rwhp. I am thinking a 408 with AFR205's or mild ported Vic Jr.s and a healthy cam should just about do it.

Just like to see these combos. Thanks for the input.
 
Zmann said:
what ever you do make sure you put a BIG enough head on it!! Atleast a 225 intake runner volume, so that woud be a big high port or an AFR 225, dont wory about the old myth about loss of torque, because with such a long stroke It wont matter, and if you dont have enough head with the long stroke you'll loose 50 -100 hp!

I would go with the TFS "R" heads WAYY before a highport. Price is what made me go with them over the AFR's. I believe I paid $1480 through summit.
mike.
 
fawcett said:
mike what are you getting for gas mileage with that big n/a engine?
what mileage would be expected with a force fed 331 with close to comparable performance numbers?
fawcett

Keep in mind that I have a "chokeless" 1000cfm carburetor. I got 10.5mpg the last time I checked it. My buddy has a 331 T-trim that makes 540/543 at the wheels and he gets worse than me when he drives hard, and a little better than me when he takes it easy.
mike.