Engine Build Choices - What Would You Choose?

All valid points, but I think this is about long term budget. Yes, 306 is a little cheaper right now, but in two years he is going to want more cubic inches. Then he has to start over.

Now, of this was a choice of 306 with aluminum heads vs. 331 with iron heads, then I would say go 306. But, it looks like he will be stuck with iron heads either way, so that is really irrelevant.
Exactly
 
  • Sponsors (?)


Way easier to add the topend later. Than being limited by smaller displacement. Umm MM&FF also have done articles showing the power differences between 306-347 builds with the "same" topend kits
I'm sorry but more displacement has more potential for hp. Why is 347 in your on screen name if you don't believe in displacement? And who said anything about expense being better? That's true no matter which direction you're talking about. More expensive heads/displacement. And as for the "new" 5.0 making 400 hp who cares. They also build a 5.8 for the cobra. Why did they do that? Why not just put the blower on a 5.0? I just don't agree about a 306. I believe in displacement that's why I'm going to build a 9.5" deck motor:nonono:

I have to say this is exactly the responses I hoped for. Not really helping in deciding which way to go but to get real people feedback is very useful. I'll continue watching responses before final decision. Thanks all!!
 
I hate to say it, but build the engine the way you want it from the beginning. He said he wanted to use Gt40 heads. Based on that it's hard for me to recommend building a short block to work with parts the op has no intention of buying. Sometimes it's easy to project our engine fantasies into advice for others instead of just honestly answering questions.

Yes, I have 347 in my screen name, because I have a 347. That's because I have the top end to use that displacement. If he was asking what engine to put under a big set of Canfields and a custom cam, I would probably recommend a 347.

A good stroker engine costs a lot more than a 306. Leave the wear parts and the machine work out of the calculation for now because it's the same either way. Actually a little more on the machine costs for the stroker because the cylinder bores have to be notched for rod clearance. The engine comes with a set of rods and a crank. Machine costs are about the same there because stroker cranks come unbalanced. I have the receipt for my last crankshaft and it was $749 for a stroker crank after balancing. You can turn a stock one for around $100. I honestly don't know off the top of my head what a good set of 5.4" rods go for these days, but I can guarantee it's hundreds more than rods you already have. You can get a set of 306 Speedpro pistons for about $200. That's a quality piston. Stroker pistons cost more money.

Kurt
 
Last edited:
  • Like
Reactions: 1 user
$1350 got me a completely balanced rotating assembly. It was a cast Scat crank, still stronger than the stocker. 4340 forged rods, SRS forged pistons, chrome moly rings and clevite bearings. That also included a new balancer and billet flywheel, oh yeah, and shipping. BTW, no notching needed with Scat i beams on a 331, so no difference in machining cost with 306 vs. 331.

Oh yeah, no "fantasy build" here, it was really done. Could of spent $1300 two years ago, then turned around and redid it this year for my new HCI, but thankful I went 331 and already have a great platform to build off of.

Joe
 
OP, what are the odds that you will be able to add a "better" topend in the near to not so distant future? If the odds are in your favor that you will be able to afford the "goods" shortly maybe stroke it and deal with a topend later. But if I were in your shoes it'd pretty much be a one shot deal. So I'd prob build the best motor i could with the parts I had or could afford. So that being said if I was building it and had a set of gt40s to use I'd go with the 302. I likke to dream now and again but when its a "one shot deal" it is what it is, there's no afrs in the near future (for me). Hope I made any kind of sense , I knew what I was trying to say maybe just didnt articulate it very well(2am). In closing, only you know your financial situation and patterns. If you have the same coming in and going out each month and gt40s are what you can afford go with the 302/306. If you feel that in the near future you will come into a winfall maybe build a build with some growing room, ie: 331 347
 
$1350 got me a completely balanced rotating assembly. It was a cast Scat crank, still stronger than the stocker. 4340 forged rods, SRS forged pistons, chrome moly rings and clevite bearings. That also included a new balancer and billet flywheel, oh yeah, and shipping. BTW, no notching needed with Scat i beams on a 331, so no difference in machining cost with 306 vs. 331.

I will never recommend someone cram a Chinese part into a Ford engine. I just never will. I've seen two of those Scat cranks split before the engine was even broken in.

Kurt
 
OP, what are the odds that you will be able to add a "better" topend in the near to not so distant future? If the odds are in your favor that you will be able to afford the "goods" shortly maybe stroke it and deal with a topend later. But if I were in your shoes it'd pretty much be a one shot deal. So I'd prob build the best motor i could with the parts I had or could afford. So that being said if I was building it and had a set of gt40s to use I'd go with the 302. I likke to dream now and again but when its a "one shot deal" it is what it is, there's no afrs in the near future (for me). Hope I made any kind of sense , I knew what I was trying to say maybe just didnt articulate it very well(2am). In closing, only you know your financial situation and patterns. If you have the same coming in and going out each month and gt40s are what you can afford go with the 302/306. If you feel that in the near future you will come into a winfall maybe build a build with some growing room, ie: 331 347

I'd be worried about this too.

No matter how you slice any of these plans, none are really good.

I think the real difference is that if you build (IMO buy) a 302 and put aluminum heads on it, even if the future never comes, you will still have a pretty kick ass setup in a light car that pretty much flies.

If you build a 347 and you never get around to the heads, it will always be a mediocre, disappointing, unfinished project.

The only solid plan would be to build the 347 from the ground up on a stand and finish it with the permanent parts, not temporary ones.
 
  • Like
Reactions: 1 user
I'd be worried about this too.

No matter how you slice any of these plans, none are really good.

I think the real difference is that if you build (IMO buy) a 302 and put aluminum heads on it, even if the future never comes, you will still have a pretty kick ass setup in a light car that pretty much flies.

If you build a 347 and you never get around to the heads, it will always be a mediocre, disappointing, unfinished project.

The only solid plan would be to build the 347 from the ground up on a stand and finish it with the permanent parts, not temporary ones.
Yes what he said. Another thing I'm curious about is how much room for the required long tube headers when using p heads is there in the factory 5, is it ample or is it pretty tight in there?
 
Ran across this engine shopping for a customer. I think the hp number is a little high for an iron head engine, but it's still a killer deal. Comes with a warranty too.


http://shop.advanceautoparts.com/we...ionPath=L1*14923|L2*15031|L3*16033#fragment-1

Kurt

Thanks again guys, all good info and comment. I'm certainly thinking through my options, might even break out the piggy bank.....
About the headers, in the FFR Cobra installation the left and right headers are swapped over so the exhaust goes forwards to allow a side exit via a J shaped connecting pipe. I have the Ford racing headers which work fine for plug access.
Anyone who would like to see some build photos,the link below should get you to my photobucket account.

Cheer, John

http://s630.photobucket.com/user/JTB3210/library/?sort=6&page=1
 
K
No way would I recommend a ATK engine. Too many horror stories. Scat cranks are hit and miss. I would have them checked out before putting them in a car.

Done a few ATK engines. Haven't had too many problems. It's a standard rebuilt engine, nothing special. Anything that comes out of China is only going to be as good as whatever they recycled it out of. If they were melting down good dish washers that week, you might get a good crankshaft. If there were still a bunch of dishes in them when they turned on the furnace, good chance your crank will break.

Kurt
 
K

Done a few ATK engines. Haven't had too many problems. It's a standard rebuilt engine, nothing special. Anything that comes out of China is only going to be as good as whatever they recycled it out of. If they were melting down good dish washers that week, you might get a good crankshaft. If there were still a bunch of dishes in them when they turned on the furnace, good chance your crank will break.

Kurt

Well, looks like I will be bringing some more cash to the table and upgrading the heads. I plan to sell off the GT40P's and take the advice that seems to be to maximize the increased capacity of the 331 and help the motor breathe better. So, with that in mind head choice (part number if possible) please for around $1000 to match with my E303 and Explorer upper/lowers. There, done it.....

Cheers, John
 
Now on to the bad news, lol.
$1000 doesn't buy heads new in box that are optimal for a stroker.

I'd look for used heads while your shortblock is being built.
twisted wedge 190 or afr 185's is what i would shop for. But both are about $500 over your budget for set. Used they should be in the low 1000's.

I also suggest forgetting the 331, it has no advantage over a 347 and they cost about the same.
 
For a 331-347 you should run the 185cc heads or bigger to maximize the combo. The tfs 170cc heads are a little cheaper than the bigger ones but again you are compromising the engine if you go that way. Hearing very good things about the new tfs r11 190cc-205cc heads. They already have everything you will need to make a crap ton of power. But with rockers,pushrods,gaskets,etc you're looking at just over 2k. The 170s are about 500-750$ cheaper with all the extras but will limit power production.
 
Here it goes. That snowball is running down hill fast. Lots of good advice above. I would agree with a Trick Flow or Afr at least 185cc. There are slight differences between a 331 and a 347. It is easier to keep the compression down on a 331 for boosted applications which is not a factor here. It also has a slightly better stroke/rod length ratio for better longevity which is more theoretical than practical, also not a factor here. If you are going to stroke it, go for the 347.

Kurt
 
  • Like
Reactions: 1 user
Rule here is that we must make you spend twice your budget. This way any time anyone asks how much a project is going to cost, we can say "make a budget, then double it".