Help 363 or 427 Cant make up my mind

You want the 4.125 Dart with the Siamese bores. Youre not going to get 363 inches out of a 4.000 bore dart block. If youre planning on a 363 youd want atleast the 190s but a 205 11r would fit the bill .
Cool gotcha, so the 4.00 bore would be better suited to stroke to a 331 or 347.
They’re the exact same block. Both can be taken to near 4.200 and are Siamese bores
so block is the same but they just come in different bore sizes? The one locally is 8.2 4.00 it isn’t the biggest deal saver he was asking 1900 I was gonna see if maybe he will take 1800, meh saves me a couple hundred bucks and no freight pay. But...if it’s a better idea to go the 363 route by using the 4.125 bore then I guess I would just wait and order that block later down the line.
 
Cool gotcha, so the 4.00 bore would be better suited to stroke to a 331 or 347.

so block is the same but they just come in different bore sizes? The one locally is 8.2 4.00 it isn’t the biggest deal saver he was asking 1900 I was gonna see if maybe he will take 1800, meh saves me a couple hundred bucks and no freight pay. But...if it’s a better idea to go the 363 route by using the 4.125 bore then I guess I would just wait and order that block later down the line.
While I don't think a 347 to 363 is a big deal, I wouldn't pay that much to another individual.
I'm of the belief that you messed up and bought something you don't need or can't afford and you should lose 25%, that's a worthwhile savings, any other time i'd prefer to have my own receipt with my name on it.
 
Cool gotcha, so the 4.00 bore would be better suited to stroke to a 331 or 347.

so block is the same but they just come in different bore sizes? The one locally is 8.2 4.00 it isn’t the biggest deal saver he was asking 1900 I was gonna see if maybe he will take 1800, meh saves me a couple hundred bucks and no freight pay. But...if it’s a better idea to go the 363 route by using the 4.125 bore then I guess I would just wait and order that block later down the line.

knowing it’s the same block now you can do whatever you want . I have a big bore 4.125 347 in mine . All it takes is the right crank and rods to get what you want
 
  • Like
Reactions: Reddevil91
knowing it’s the same block now you can do whatever you want . I have a big bore 4.125 347 in mine . All it takes is the right crank and rods to get what you want
I was going to ask you about the motor bc I thought you had a 363 with twisted wedge heads yourself, so I was like it has to be possible. Then I do you say something about and it must be a story. Im sure you explained it in your thread. Are you happy with the 347? I guess I’m not understanding why there is a big bore. Like I looked around on fordstokers and they have 331,347,363 then options for big bore 331, 347 etc. I also get co fused with the piston option. I know TFS sells there specific ones, read another thread about some others used. Ford strokers has an option for twisted wedge valve reliefs but then the pistons options is something about flat top, then 14 or 20cc dished. Truthfully idk if I even need a 363 vs the 347, or whether it’s better to piece and build it slowly vs just saving and ordering one built from someone like ford strokers, chp etc.
 
I was going to ask you about the motor bc I thought you had a 363 with twisted wedge heads yourself, so I was like it has to be possible. Then I do you say something about and it must be a story. Im sure you explained it in your thread. Are you happy with the 347? I guess I’m not understanding why there is a big bore. Like I looked around on fordstokers and they have 331,347,363 then options for big bore 331, 347 etc. I also get co fused with the piston option. I know TFS sells there specific ones, read another thread about some others used. Ford strokers has an option for twisted wedge valve reliefs but then the pistons options is something about flat top, then 14 or 20cc dished. Truthfully idk if I even need a 363 vs the 347, or whether it’s better to piece and build it slowly vs just saving and ordering one built from someone like ford strokers, chp etc.
The big bore comes into play being that you start at 4.125 bore and then you use a 3.250 stroke crank like you would in a stock block 331 . So you get the benefit of being able to rev it higher with the added cubic inch . Where as a Stock production block 347 uses a 3.400 stroke crank to achieve the 347 inches and a 3.250 stroke to achieve 331 inches .

In a dart block when you use a 3.400 stroke crank and have a 4.125 bore you end up with 363 inches . No reason not to do it really .

My combo is a 4.125 bore , 3.250 stroke 347 . It’s actually 4.155 now after having to have been cleaned up a bit from some mis haps . Has a custom diamond piston in it with TW valve reliefs . You can have a custom piston built to whatever bore and dish you need to achieve your CR you’re looking to get to , that’s what I did . I have 20511r heads on mine . Brian Freezy did the cam and morel link bar lifters in it .

Ford strokers is a great option if you don’t have someone local
 
  • Like
Reactions: Reddevil91
After doing several 351w swaps, what I found is that there was a reason Ford didn't put a 351w in a Mustang. It doesn't really fit. You will need a hood (unless you get creative with the K-member, etc), pan, intakes, headers, brackets and a bunch of other little odds and ends. We "make" it fit and it does once you address the fit issues. Lot of guys drop the K-member but that changes the front suspension geometry which affects handling, among other things. I also did a 460 based engine (514) in a '86 Fox Mustang and it is roughly the same amount of work to get it in there as a 351w with the exception of the master cylinder. The booster hits the valve cover so we had to go with manual brakes, which is no problem given the application (strip/street with emphasis on strip).
 
I've still yet to see anyone come up with a good explanation of why anyone would need a 427 over a dart 363 in a street car when running an aspirated engine.
What, so you can run like 3 pounds of boost less?
At this level of build, that number is negligible. If you were talking a stock 302 bottom end, a few lbs is a lot, each one creeps you closer to some level of risk, that's a time when lower boost matters.
I still believe the 351 adds complexity and cost, without really giving anything in return.
Ok so help me out. I'm trying to decide as well as I thought about getting Prestige Motorsports to build me a 427 as it's only $500 more than doing a 408 and 50 more rated hp. I'm not trying to do a max build and the car will not see the track. The 427 rated @ 500 crank hp/tq I'd be cool with 400-420 rw. The thing is for a long block it's around $8194. EFI car and manual N/A by the way.

That particular 427 runs a PM built 185 cc, 59cc head
cam @ .050 is 243/251 and .565/.549 lift
all forged

If I went dart I could get a 408 or 427 for around $9397 (gotta call and see if that inclu. oil pan I don't think it does) and a 363 would be around $8997. I need to get with Jim and talk about projected numbers for what I want to do and which heads/cam would be good to use. Either way I intend to use a TFS R (not box) intake and yes I know the box would yield more but not trying to maximize and that intake is that much taller than the R. Plus I love the look of the R better.

So yeah now if I went dart and reading what you said, do I want a 363 or 408/427? I do love the idea of having a little more room with the 363. I guess my question to you and to Jim would be telling him what I intend to use the car for and then him telling me rather I can achieve my goals or around the same thing from a 363 as the 408/427.
 
Last edited: