Hey guys i have a 351w block sitting in the garage next to my AFR 185s.. im starting to look at internals but not sure what to get. im looking to get at least 400rwhp for the street. i was looking at kb pistons but im not sure which ones will help me do the job. please help me out with some combos (pistons, rods, lifters, crank, cam, everything!) that will help me get at least 400 rwhp. if any additional info is need please let me know thanks.
351w internalss help!!!!!!!!!!!!!!!!!!
- Thread starter 67staaang
- Start date
-
Sponsors (?)
LMan
Founding Member
You need a friend there to guide you thru the process...before you waste money and time. Is there a Ford-savvy engine buddy near you that can help?
dennis112
15 Year Member
If I was in the same situation and needed to buy all new guts, I would look at a 408ci Stroker kit from some place like fordstrokers.com The kit will include a matched crank, rods, and pistons depending on your desired compression ratio. Once that is determined, then you can decide on cam and lifters.
SoCalCruising
Founding Member
He said 400 at the wheels. With an AOD, that means about 500hp at the crank. It will take a pretty good 357 (.030" over standard bore 351) to get 500hp and behave nicely on the street. Not impossible, but much easier if you stroke the motor. I like the 393 with a 6.2" rod. Use a cast crank (like Scat) and good H-beam rods. See www.ADPerformance.com to get an idea on the price of stroker kits. Of course, he has the 408W, too. If this is an older block and standard AFR springs on the heads, a roller cam conversion will be pricey. You would be well served to just use a flat tappet cam with 290-300 degrees duration at .008" lift, or about 230-236 at 0.050". Get as much lift as you can and not bind up the springs. I think the standard springs are good to .550" lift. TO get to 400RWHP, you may need a Victor Jr. intake and 750 cfm carb. Anyway, my $.02.
SoCal, why do you prefer the 393 over a 408? I'm at a similar point as 67 is at in his build, and I'm trying to decide between those two combos. I know the basics from reading old posts, but never hear much real world feedback. If you could, please elaborate a bit on your choice. Thanks!
I think I can answer this. When stroking an engine you have to be careful when dealing with the rod length vs stroke of the piston. When you increase stroke, you usually do it at the expense of a shorter rod. What this means is that there is much more lateral (sideways) force on the piston. The increased lateral force causes accelerated parts wear and often premature failure.
The 393W still has a decent ratio and can live a long and healthy life. Not a big difference from the 408, but you have to draw the line somewhere.
Thanks BottleFed70. I have read a bit on lateral forces and rod ratios in various articles as well as here on StangNet. What I never seem to find an answer to is if you were to compare a 393w to a 408w with both engines being otherwise similar, what would be the pros and cons of each? Mind you, I'm talking about a street application, so would the 393's benefits of a better rod ratio make for that much better of a street motor than a 408? Of course, it depends on the build quality as well, but would a 393 last noticeably longer than a 408? In short, I'm asking if when it's a matter of 15 cubic inches, is it better to bet on rod ratio or displacement? I know there are lots of variables to consider, but like I mentioned in my previous post, I'm also looking to make around 500hp with my project. And yes I know, it's a lot of hp for the street, it'll suck gas and so forth. I just like SoCal's line of thought of it not being impossible to behave nicely on the street and still make power. Thanks again guys!
Chris
Chris
brianj5600
Active Member
I don't think rod ratio will help a 393 enough to outrun a 408. I have not heard of 408s having reliability trouble either. A 454 BBC has a lower rod ratio than a 408 and they seem to last ok.
The 408 is personally what i would and hope to buy in the future. As for reasons why you may decide to go with a 393 stroker instead is that the cylinder walls at the bottom do not need to be machined for rod cleaerence where as with a 408 stroker they do. so it is a little cheaper to do a 393 stroker then the 408.
SoCalCruising
Founding Member
You can certainly make the 400rwhp number with a 357W - it just takes 500fwhp to do it, given the auto tranny. You will find that a 450fwhp number is pretty straight-forward to achieve based on any number of similar parts combos. That is, it doesn't take exotic stuff to pull it off. 500fwhp is tougher and requires more thought, or a different kind of build. It certainly is more expensive. The key to the power will be the header/heads/cam/intake combo. The power number will probably come at >6000RPM, so you have to plan accordingly, which is why more money will likely be spent, especially if the build is in the hands of an amateur builder (like me). A professional engine builder is able to do more custom work (porting, better cam selection, for example), that's how they make their living - by being better at it than we amateurs are and not having to pay someone else to do it. We generally have to throw money at it to achieve the same thing. That's not always the case - there will be exceptions - but I think it is the rule.
As for 393 vs. 408: BottleFed70 answered for me pretty well, but my answer really depends on the purpose for the engine. If you drive the car <5000 miles a year and aren't really interested in an engine capable of running 50-100K miles, then the answer is that there is no substitute for cubic inches. My personal goals are to have an engine that is just as strong running at 25K, 50K, etc. miles as when it is fresh. I mean, that's the plan. So I try to keep the rod ratio at 1.65 or better and the piston compression height 1.25" or more. Now, I break those rules, too, but that's the general idea. My current 331ci motor has a rod ration of 1.66 (good), but a c-h of just 1.175. So, I made a compromise. I was not willing, however, to compromise to 1.09" c-h or 1.59 rod ratio, which is what you typically get with a 347. Also, I consider readily available parts and their costs. 393 kits with a long rod - I distinguish this from the 302 rod based kits which I would not use - are readily available, have a good c-h and a pretty good rod ratio of 1.61 or better, depending on the rod (6.2" or more). I would build this engine so long as I was building a <6500RPM motor. If I was building for higher RPMs, I'd look at the 383ci. This is all just my opinion, so take it for what it's worth.
As for 393 vs. 408: BottleFed70 answered for me pretty well, but my answer really depends on the purpose for the engine. If you drive the car <5000 miles a year and aren't really interested in an engine capable of running 50-100K miles, then the answer is that there is no substitute for cubic inches. My personal goals are to have an engine that is just as strong running at 25K, 50K, etc. miles as when it is fresh. I mean, that's the plan. So I try to keep the rod ratio at 1.65 or better and the piston compression height 1.25" or more. Now, I break those rules, too, but that's the general idea. My current 331ci motor has a rod ration of 1.66 (good), but a c-h of just 1.175. So, I made a compromise. I was not willing, however, to compromise to 1.09" c-h or 1.59 rod ratio, which is what you typically get with a 347. Also, I consider readily available parts and their costs. 393 kits with a long rod - I distinguish this from the 302 rod based kits which I would not use - are readily available, have a good c-h and a pretty good rod ratio of 1.61 or better, depending on the rod (6.2" or more). I would build this engine so long as I was building a <6500RPM motor. If I was building for higher RPMs, I'd look at the 383ci. This is all just my opinion, so take it for what it's worth.
if i built a 393 would it last as long as a 351w? ive been hearing different things but i want to come to a conclusion about this issue.. what combo i have in mind at the moment is my afr 185s, comp cams, and victor jr intake and not sure about headers.. how does that sound?? any recommendations? pistons?
LMan
Founding Member
SoCalCruising
Founding Member
http://www.adperformance.com/index.php?main_page=product_info&cPath=71_95&products_id=471
Look at the combo at/near the bottom of the page. It Will give you an idea about a 393 combo. The price would increase by $25 as you would need the dish option to get the compression down. There is also a more expensive kit above on the same page - all forged and couple hundred bucks more.
The only part of your combo that will make it tough to reach your 400rwhp goal will be the heads. The AFR 205s would be just about perfect, IMHO. The 185s are a little small, but you can make up for that to some extent by using more cam. The FRPP 392 crate motor with only a swap to AFR 185s did make over 535fwhp using the XE282HR cam, which it comes with from FRPP. This is without accessories and almost no water pump (loose belt), though. So, about 500fwhp with accessories and a water pump. Pretty close to what you are looking for.
As for longevity, I would have no worries if using a 6.2" rod, or longer and used a 6000RPM rev limiter.
Look at the combo at/near the bottom of the page. It Will give you an idea about a 393 combo. The price would increase by $25 as you would need the dish option to get the compression down. There is also a more expensive kit above on the same page - all forged and couple hundred bucks more.
The only part of your combo that will make it tough to reach your 400rwhp goal will be the heads. The AFR 205s would be just about perfect, IMHO. The 185s are a little small, but you can make up for that to some extent by using more cam. The FRPP 392 crate motor with only a swap to AFR 185s did make over 535fwhp using the XE282HR cam, which it comes with from FRPP. This is without accessories and almost no water pump (loose belt), though. So, about 500fwhp with accessories and a water pump. Pretty close to what you are looking for.
As for longevity, I would have no worries if using a 6.2" rod, or longer and used a 6000RPM rev limiter.
Similar threads
