306 supercharged 450fwhp - Input needed

[Sinister66]

So I was reading this article and I'm looking to duplicate their build.

5.0 Engine Buildup - 5.0 Mustang & Super Fords Magazine

I have my engine torn down and I'm ready to order parts. I just want to make sure I get the right combination. Now at 10psi what compression ratio should I shoot for(9.5-1, 9.0-1)? Forged pistons are a must right? I can't get away hyp's? Can stock rods/cranks hold up at 450hp or should I order some forged I beams? Thanks for the help!

 

[Sinister66]

Sorry, maybe it was a bad acronym. By FWHP I mean Flywheel horsepower, not front wheel drive.

 

[95BlueStallion]

Ive heard some say hyp pistons can withstand up to 500 crank hp, then others say no. Everyone has a different opinion, and lots of folks have had better luck than others. I personally would want to make sure its done right the first time, especially when were talking about boost. I would buy forged internals and never have to worry about it. Then all you need to worry about is splitting your block when you up the boost to 18psi...

 

[Supercharged306]

Boosted Engine

First off never use HYP. pistons in any type of boosted applications. Go with a 9.5 max. and 8.5 min compression depending on fuel(9.0.1 should be fine). Make sure you go with a Cometic head gasket. The big thing that fails is the connecting rods via bolts use APR 9000 bolts or L19 is you have the money to have the rod machined heavily. H beams would be my choice with the 9000 bolts. I have a supercharged 306 drag car and I will tell you don't go cheep. I have seen people do it and boy does it cost. If you cheat anywhere it will haunt YOU!!!! Main stud girdle is a must as well, considering the main caps walk at about 500hp. If you plan on revving the engine past 7,000 I would also use a solid roller cam, roller lifters, shaft mount rockers. I run T&D rockers they will cost you but they are well worth the money spent. You can make over 1000hp (Safely) on a small engine if you do it right.

 

[2000xp8]

First off never use HYP. pistons in any type of boosted applications. Go with a 9.5 max. and 8.5 min compression depending on fuel(9.0.1 should be fine). Make sure you go with a Cometic head gasket. The big thing that fails is the connecting rods via bolts use APR 9000 bolts or L19 is you have the money to have the rod machined heavily. H beams would be my choice with the 9000 bolts. I have a supercharged 306 drag car and I will tell you don't go cheep. I have seen people do it and boy does it cost. If you cheat anywhere it will haunt YOU!!!! Main stud girdle is a must as well, considering the main caps walk at about 500hp. If you plan on revving the engine past 7,000 I would also use a solid roller cam, roller lifters, shaft mount rockers. I run T&D rockers they will cost you but they are well worth the money spent. You can make over 1000hp (Safely) on a small engine if you do it right.

I'm not in agreeance on pretty much anything in this statement.

Hypers, while not the best, usually outlast the stock block, rarely do you see anyone with a 5.0 complaining of piston damage. Would i rebuild an engine with them? No, but then again, i wouldn't build a 306 either, i'd certainly go to a 347.
Cometic head gaskets are not only unecessary, but if the engine detonates, the pressure has got to go somewhere, and if it's not out the head gasket it goes somewhere catastrophic. A properly setup engine is fine with the felpro 9333pt1's. And if you blow a head gasket, either you didn't install them right, the engine detinated or overheated.

Main girdles are worthless, they just keep your internals off the pavement when the engine goes.

7000rpm with a solid setup in a stock block? That's just insanity, that should survive about a day or so on the street.

 

[JustaMustangguy]

First off never use HYP. pistons in any type of boosted applications. Go with a 9.5 max. and 8.5 min compression depending on fuel(9.0.1 should be fine). Make sure you go with a Cometic head gasket. The big thing that fails is the connecting rods via bolts use APR 9000 bolts or L19 is you have the money to have the rod machined heavily. H beams would be my choice with the 9000 bolts. I have a supercharged 306 drag car and I will tell you don't go cheep. I have seen people do it and boy does it cost. If you cheat anywhere it will haunt YOU!!!! Main stud girdle is a must as well, considering the main caps walk at about 500hp. If you plan on revving the engine past 7,000 I would also use a solid roller cam, roller lifters, shaft mount rockers. I run T&D rockers they will cost you but they are well worth the money spent. You can make over 1000hp (Safely) on a small engine if you do it right.

As with 200xp8. Completely disregard anything this guy said. He is clearly uneducated.

First, the whole point of going a 306 is so that it is a refeshening. It allows you the use of using your stock rods and crank. A 306 build is kinda a budget build, which is fine. Now if you were to replace either of those parts, you'd be a fool not to do a 331 or 347ci. BUT, for a 450hp setup your stock crank and rods will be plenty fine.

Secondly, hyp pistons are good pieces. Those pistons(as long as they are quality pieces) are going to outlast your stock blocks capabilities. As for him saying they are bad for supercharging? Well lets just think about the '03-04 Cobras for a minute. I think the biggest thing here should be the tune. You must get a quality tune. Because if you don't it won't matter if your got forged or hyp.

 

[ddonaca351]

(imho)

Hypers are good parts, I run them in my Cleveland... BUUTTTT I would never run them in a poweradder application. To me the cost savings and weight savings isn't worth the risk. But thats just me... I'd go forged and know that they are good to go.

I'd also go with good I beam (or in my case H beam... I'm an overbuild it kind of person) rods and know that they are going to hold the load.

I mean look at it this way, would you rather save up for an extra 3-4 months to afford it and have a motor that will withstand 10 years of abuse, or rebuild it a little cheaper right now and then have to rebuild the motor again in 2-3 years?

Know what I mean???

Anyhow, tune will also be key (it always is) budget another 500 for a day with a good tuner on the dyno. You've got 10-15K in a build, spend a few hundred on the tune to let it live a long life.

A stud girdle is also a good idea, if for no other reason than to help keep the caps from walking. And just f.y.i. I have seen a couple stock blocks let go in the 500 area... and heard about ALOTT more that did the same thing, so better to be safe than sorry. Again a few extra bucks for the girdle can make the difference. You're only talking gaps of half to 1.5 thou, so it doesnt take much to get metal to metal... and loud noises and smoke come right after that.

Again imho, when in doubt overbuild the foundation.

In a year or two you wont miss the extra bucks, but if you're having to rebuild it again cause if let go... you'll really wish you had.


Dave

 

[2000xp8]

To the Original poster, make this a little easier by suggesting how much you have to spend total on the shortblock, then we could suggest where to spend it.
That includes labor if any, and parts.

Here in NJ, local pricing on engine labor is $1000 and up. (i paid $1200 for machine work and assembly on my last engine)
You go full bore with the parts and you are at another grand, which leaves you pretty much in a situation that you could of just bought a built 347 shortblock.

Also IMO, the less boost you need to reach your hp goal, the better.
Spend your money right and you can get over 400rwhp without any supercharger.

 

[blackened88lx]

Wow, what a cluster**** of horrible advice.

Here's your guide to 500rwhp for dirt cheap.
First thing's first, if it has boost and a stock block, DO NOT spend a dime on the bottom end. You don't need a good crank, you don't need good rods, you don't need good bolts. The bone stock rotating assembly will long outlive the block. **** girdles, that junk doesn't work.

Personally I would use the stock forged pistons, but if you are forced to bore it because of the cylinder wall condition, go with a cheap forged piston, 9 or 9.5:1. Hypereutectic pistons are not "good" parts. They may be good enough for some applications, but that's about it. These pistons do not shed heat for ****, which is not a good thing in a boosted application. A lot of the heat tries to shed through the rings. With a poor tune, detonation, and a lot of heat, they will explode. They won't burn up, or get a hole in them, they will grenade.

Like someone else mentioned, don't bother running good head gaskets. The Fel-pro 9333s work great, and so do the 10111s or whatever they are. Think of your head gaskets as a fuse. When something goes wrong you would rather put head gaskets in it than a motor.

Pick pretty much any head other than E7s. Use an F-303 cam. Use any intake other than stock.

Go to a GOOD, I mean GOOD tuner, and have it dyno tuned. Put pulleys on it til it makes the desired power, and don't spin it over 6k. Don't be afraid to make 15+ psi to get the power number you want.

 

[bentley429isBAC]

Yep.

 

[Supercharged306]

I think when it comes to all this information you need to talk to real engine builders. I own a race shop in WA and build engines all year round. If you plan on your engine surviving for long term trust me. Most of us don't put a Supercharger on our car and then drive like GRANDMA!!!!! If you plan on having fun with the engine build it right the first time. A 347 is a good choice but it is not what you implicated. I have a Vortech V7 on my 306 26PSI 89 Mustang S/G. I have been running my setup for a long time. I have been on Pinks All Out and most NHRA National and Divisional Events on the West Coast. People never really understand what it takes to make a little engine right. Most my customers want cheep but then thank me when **** doesn't go wrong. While guys all over are paying more money to fix the problems we are having fun. Don't by cheep parts IT WILL HAUNT YOU!!!!!!

 

[bentley429isBAC]

Pretty sure this guy is looking to stay stock block. Why the hell would anyone suggest putting in a good rotating assembly in a block thats possibly going to break and ruin the goods. If he is asking if he can run hypers clearly he is looking to save some $$. My 302 has been together for 3 years, stock block, pistons, rods, crank has been used and abused that whole time and has been at least 475ish to the tires the whole time. Hasent given up yet knock on wood and cost me very little engine wise. OP, what your looking to do will be fine with a stock freshened up bottom end some half ass h/c/i will do and 10 psi. Get some 42's 255 intank possibly a nice inline pusher if needed and get it tuned. Thats it and have fun. Keep it under 6k and it will last a while.

 

[2000xp8]

I think when it comes to all this information you need to talk to real engine builders. I own a race shop in WA and build engines all year round. If you plan on your engine surviving for long term trust me. Most of us don't put a Supercharger on our car and then drive like GRANDMA!!!!! If you plan on having fun with the engine build it right the first time. A 347 is a good choice but it is not what you implicated. I have a Vortech V7 on my 306 26PSI 89 Mustang S/G. I have been running my setup for a long time. I have been on Pinks All Out and most NHRA National and Divisional Events on the West Coast. People never really understand what it takes to make a little engine right. Most my customers want cheep but then thank me when **** doesn't go wrong. While guys all over are paying more money to fix the problems we are having fun. Don't by cheep parts IT WILL HAUNT YOU!!!!!!

If you are not into cheap setups, why exactly do you run a 306?

 

[Supercharged306]

I am running a 1968 Mexican 302 well 306 engine. Despite what the word is the Mexican block has bigger main caps and thicker webbing not higher nickel content. A few friends of mine and I tried to come up with small cubic inch high HP engines. I have a 408W stroker as well. I am really into small engines making big power to prove a point that not all race cars need a big block with 605 CID to win and be fast. Most people ask the same thing WHY. It is all about what you like. I have guys that have ripped out killer pushrod V8's to go with Modular engines, guys that have put engines that are so big you have to move the firewall and relocate the front struts. Why I don't know 950HP=950hp no matter how you do it BB or SB. I think my passion is to see small engines that people think are a waste, take them and turn them into unknown sleepers that you can drive to the track and run a 8.84. In all fairness I think that strokers are the way to go but when you got something that can work and works good wait until something happens and see where your creative mind takes you.

 

[Supercharged306]

That is one wicked truck!!!!! I drive a 2002 Ford F150 Harley Davidson s/c all hooked up. Not many people Extrude Hone i think it's great!!!!

 

[2000xp8]

That is one wicked truck!!!!! I drive a 2002 Ford F150 Harley Davidson s/c all hooked up. Not many people Extrude Hone i think it's great!!!!

Thanks for the compliment (if it was directed at me)

They probably don't extrude hone, because it's expensive as hell, i happen to strike a deal on a bare set of heads already done, that someone else couldn't pay for.
I got them for the extrude hone cost.

I understand your points about doing it once and doing it right, unfortunately that puts your engine too far above the value of the entire car in most cases.

Honestly, i feel that most people that need a new engine should just buy an explorer engine, add a cam, then an SC and be done with it.
The engine value is only like $500.
Slap the SC trim on for another 2 grand and you are almost done after injectors a pump and a meter, 400rwhp is easily possible.

 

[blackened88lx]

at least 475ish+++ to the tires

Fixed

I am running a 1968 Mexican 302 well 306 engine.
take them and turn them into unknown sleepers that you can drive to the track and run a 8.84.

So let me get this straight. You are running a stock block 302 that you drive to the track and it runs 8s???

 

[Bullitt95]

I'm only a Vortech V2-SQ 6-8psi blower away from having 450hp/450lbft at the flywheel myself.

 

[Shaun1212]

My Opinion..........

I've been racing fox mustangs for almost 20 years. Have had lots of friends go well into the 10's without touching the bottom end, other than flycutting pistons for bigger lift cams.

 

[90lxcoupe]

This is the worst thread ive ever seen, so much bad advice.

Bentley, Blackened, and 2000xp8 said it best. make the power with a 302. decent aluminum heads, cam and a good intake. Also, consider a turbo, its much more efficient. superchargers use power to make power, a turbo uses wasted energy to make power.