Are you going with std bore? .020 over? That will also affect compression ratios. I've also been looking at some of this info in hope of soon building a WAP block. There was a guy on her just recently sold a set of tf heads for.....wait for it.....


$400.

Because he needed the money. That just absolutely blows my mind. I was willing to pay $1000....but oh well. Another guy right after him sold a set for $1500. They are out there.

But I believe a 12cc dish will give you right at 10.0:1 and 11cc will be like 10.3-10.5:1 with pi head combustion chambers and also depending on bore size. The larger you go on the bore size, the greater your compression will be but not by a whole lot. You should be good with 10.5:1 at 91 octane. So I've been told anyway. I personally haven't done it. But I also know that with trickflow heads you can go higher with timing and compression because of the better design. I'm on the lookout also for some trickflow heads. When I find the right ones, I won't hesitate.


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I'm going with a .030 overbore. This cuts down my choice of pistons, i may end up going with forged even if it's overkill. I've been using this website: http://www.csgnetwork.com/compcalc.html
to try to figure compression ratio, but i'm getting wild and crazy numbers. Maybe i'll have to forget the shortcuts and use the calculator : p So far, it looks like i'll need about a 15cc dish to arrive at 10.5 to 1. I tried to plug in the factory numbers to see if i get the factory compression of 9.74 but it's way off... which is why i'm looking for input : )
Man, somebody hit the jackpot with $400 TFS heads... unless they had issues... Have you already got the WAP block? ..regards, kevin

 

Just curious, why do you need all that specific information on bore spacing, connecting rod length, journal sizing? Are you doing the machine work yourself? Even if you are assembling the stuff yourself, you would be measuring these things anyways.

As far as cams, I highly doubt you would find a set of cams that are going to give you more low end and mid range power than the stock cams unless you go custom. And if you go custom, why would you want them set up to make more low end power? You doing some towing with your Mustang?

 

Put an 8cc dish piston in it, with a .030 over setup. Get it up close to 11:1, it will run fine on pump gas and be way more responsive. My big bore is right at 12:1 and runs perfect on 93. Cams will also affect the engines sensitivity to octane, large cams will bleed off cylinder pressure down low.

 

No towing for the mustang, but there are lots of big hills around here : ) The reason i'm looking for accurate information on the engine is to reassure myself that i'm buying the right stuff. There's a lot of conflicting information on the net, but i know there are people who've been down this path and they've sorted through it. I'll be involved with putting the shortblock together, but i'm going to pay an expert to show and tell me what to do. This will probably be the only time i "build" an engine, and i want to understand the process. I keep notes on everything, and if those notes are useful to somebody doing the same thing i'm happy to share... hence the details on the engine. As for cams, again, i've run into lots of conflicting information. Even with the collapse of oil prices, i'm looking for fuel economy, and since most of my driving is on the highway, low-rpm torque is the most useful. And if it puts less junk in the air per kilometre, i get to feel all noble and everything...
So, when you say "custom" cams, what cam specs come to mind? ...regards, kevin

 

If fuel economy is your concern, stay with stock cams. There is no way around it.

 

I've found one for pretty cheap I plan to get. Just waiting for the money to hit my pocket. But I believe that with fine tuning and very cautious and conservative driving habits, comp stage one cams will give you exactly what you're looking for with a good balance between mpg and rwhp. It's already been figured out for you really. I think if your going to build an engine to be naturally aspirated, you should go at minimum 10.5:1 or 11:1 if it's been proven to work on pump (highest you can go safely), get your heads ported and get some stage one cams. I think in a mustang you will be very satisfied. And unless the motor is already bored, I wouldn't go over any more than .020 over. The added .010 over for .030 over isn't worth much in hp vs ci. The little added displacement won't be enough to make a different in power to warrant the loss in block strength....020 over is plenty.

What do you have for a tranny? Auto or 5 speed. 5 speed will also give you better gas mileage. I know a guy with a 6spd cammed whipple Lightning making over 600whp and gets 20+ mpg. All the auto guys with the same engine setup gets about 13-14mpg.


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Good point on the tradeoff between a tiny bit of extra displacement vs block strength, but it's going to have to be .030 over to true up and clean up the cylinders. From what i've read, this is the maximum most builders are comfortable with. As for compression, the chap who's doing the machine work says 10.5 to 1 is my best option. Hard to find any verified information on what a .75 compression increase makes on either power or economy. I'll find out : )
I swapped in a "Viper spec" T56 last year, with a .50 6th gear (2.66 1st gear). Probably the best upgrade i've done. Along with LT headers, it's made a nice improvement in fuel economy and fun. Using imperial gallons (i've been around that long), the best highway mileage after mods is 34.5. And yes, it can do burnouts. Not that i've tried, or anything... ...regards, kevin

 

The chaps doing the machine work are keeping you safe as well as them selves.

Grab a set of stock 4v flat top pistons and run your stock cams. Youll appreciate the umph!

 

I like the way you think, 96black, but flat top pistons would give me something like 11.6 to 1, using a .041 compressed head gasket. I'm not sure if 91 octane would prevent detonation, especially on hot days. Have you run a setup like this? ...regards, kevin

 

If this is an N/A engine, that you want more low-end/mid-range torque (which I assume you won't be revving much past 6200-6300rpm), I'm confused as to why you are even going through the hassle of a forged bottom end...you will be making maybe 300w with the bump in compression....seems like a lot of money to spend for the power you are getting, especially when you can use stock parts and be completely fine (crank and rods...pistons will obviously need to be replaced due to the increased bore). Am I missing something?

 

Subscribing since I've acquired a teksid block to build a 2V specific for a spec racecar. Unfortunately I'm limited to what parts I'm allowed to use. Hope to learn something here.

 

01GT, you're correct, i doubt this engine will ever be north of 6k rpm, and i am looking for low to midrange power. I know a forged rotating assembly is overkill for somebody with my driving patterns, but i'm only going to do this once, and i want it to be as close to unbreakable as i can make it. I do like to drive spiritedly once in a while, and it seems like a lot of time, money and effort to put a new engine in the car... therefore i can justify extra few dollars spent on peace of mind. Did i mention that i only want to do this once? Besides, i don't indulge myself like this often, and i do like cool stuff : ) I know, i could just buy a newer car with a more sophisticated powerplant, but where's the satisfaction in that? I got the forged crank with the block, so i'm part way there anyhow. If anybody reading this has a nice set of forged rods and .030 over pistons cluttering up the shop, and you could use a bit of cash to pamper your spouse because you forgot about valentine's day, well...
Here's the cleaned-up block, waiting for the align hone. ...regards, kevin

 

Another proven rod, which is also very inexpensive is the boss 302 rod. They have handled well over 600rwhp and lived and they cost less than $200 for a set to your door from places like Tasca ford and other dealers alike.


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Did you already bore .030 over? Thats a bad idea to do so anyways. Unless your bores were scared up from the previous rotating assembly, NEVER bore more than you need. .030 is not going to give you a major compression bump form .020 over and so on. Now, if something happens to one of your bores, you have no choice but to sleeve the block. Your most contributing factors to compression is deck height, valve size, combustion chamber size and piston dish. If you go out of your way to get a big dish (18cc-15cc) but a smaller than standard combustion chamber (38cc), your going to get a higher compression than you expected. I am assuming your block is getting decked? Depending on how much they cut down, that will also play into your compression.

As far as your short block, the only two things you need to replace for a high hp NA 2v is the rods and pistons. Your stock 2v crank is good to least 600 hp. Their is 0 reason to pour money into a forged bottom end with a 2v NA build. The MOST amount of power you'll see out of an NA 2v is 400-425 hp and thats sitting around 14 compression and HUGE NA cams. iRoush got past 400 hp pretty easily with his 2v NA Teksid build:Project: e85 Torpedo - Forums at Modded Mustangs Highly recommend picking through his build thread to get an idea of what you will run into with a Teksid build. I also just got done doing a 2v Teksid build.

I can tell you now, running 91 octane pump gas, you can see 350 hp fairly easily but you WILL sacrifice gas mileage. If you want a moderate compression, mild 2v build you might not even see 300 hp to get the gas mileage you want. The only way to can run anything past 10.5 compression is with a corresponding set of cams, and no, you don't need custom cams..... You just NA cams: Modular Head Shop 4.6L N/A Street / Strip Camshafts

 

Yes, x7, i had no choice, the block is .030 over to clean it up. Since the purchase of the Teksid included the forged crank (it's a '99 Cobra block), i'm not splurging on a crank. I'm going to go with forged rods and hypereutectic (unless i find an offer i can't refuse on forged) 15cc dish pistons. Any strong feelings about silvolite? At this point, i'm planning to port/polish my PI heads and use them (unless i find an offer i can't refuse on TFS heads), so the combustion chambers will be stock 42.5cc. The decks are pretty straight and flat, but i'll make sure they're as close to perfect as possible. I'll use head gasket thickness to fine-tune CR. I spent yesterday afternoon de-burring the block and grinding and filing all rough casting and flash areas (there were quite a few, particularly in the timing gear areas, and beside the main bearing shoulders). I actually picked off a couple pieces of flash easily with a fingernail, which is why i spent all that time in "type A" mode. My plan is to go for 10.5 to 1, although i've talked to people who are running over 11 to 1 (with big cams) on 91 octane with no problems.
Cams are a whole book themselves, thanks for the MHS link. I know i'll trade some fuel economy for some power, i just need to figure out how much is acceptable. Power is fun, but i'm a Scot... My cam research is ongoing.
Thanks for the link to e25 torpedo, epic build! Too bad most of the photos are gone. Did you end up with what you wanted on your Teksid build? Details!
The engine in the car now is completely stock (with LT headers, a Diablo 91 tune and 75mm TF TB and plenum) , so 260/300... when new. It's over 200,000km now, so i'm sure some of those horses have retired. If i can get 300rwhp somewhere below 5500rpm, gain some torque, and have an utterly dependable DD for another 200,000km, i'll call it a win. The Teksid/MM full suspension/battery relocation weight reduction on the front wheels is an added bonus. I haven't "built" an engine since high school, and i doubt i'll build another, so i want this to be a good one : ) ...regards, kevin