390 stroker engines

[wrench87]

i just purchased a 70's 360-390 block with a standard bore i would like to stroke it and possibly make 500 hp. i will be using a hydraulic roller and fuel inj either keeping my mass flo or dumping the mass air meter and using a red line computer with the 1000 cfm t body. what compression ratio would be better for the street 9.8 or 10.5? i would like to use the bb chevy rods but what would make a better engine the 3.98 stroke or the 4.125 and why?.
what hp can you make with out of the box edelbrock heads? what would numbers should i be looking at for cam shafts for duration and lift.
just looking for opinions and helpful ideas from people who done it already.

[undy]

You're build will have to be somewhat radical to realistically achieve your 500hp goal. The Eboks will also have to be ported as well to achieve it. (suggest Keith Craft's stage II Eboks) I would suggest a 4.25" stroke crank and 10.5 - 11.0 to 1 compression. The cam you'll need to run will bleed down cylinder pressure which will result in a lower dynamic compression ratio. Pump gas (91-93) will stave off detonation and keep the ring lands in place. Scat's setup utilizes BB Chebby rods and can give you a 3.98", 4.125" or a 4.25" stoke.

Dave

[Barry_R]

Jay Brown and I are working on a Car Craft engine build article that covers that exact combination right now - literally right now.

We can't really give away the full details as a courtesy to the magazine folks - but we were able to hit your target with Undy's combo... on a budget.

[Dwight]

A buddy of mine, Colin build a 390 with the Edelbrock kit (heads, cam, intake) for less than $5000. That's $5000 for parts, machine work, everything. He sold the Shell Valley Cobra. The new owner called him a couple of months later complaining that the car only made 386 rear wheel horsepower. Colin had told him the motor should make 450 HP. Colin explain rear wheel and flywheel HP and the guy was happy.
You don't have to spend $10,000 to $15,000 to may a lot of Horse with a FE, even a 390. Just the correct part and put it together correctly.
With 386 rwhp in a Cobra, there are very few street cars that can stay with you from the red light. Now bragging about how much dyno horsepower you have is different. You have to spend the money.

Dwight

[Dwight]

wrench 87
How much hp is your 342 making? You can get 450 hp if it is tuned and has the correct parts, custom chip, etc. You need to have a good "Mustang shop" dyno and tune your motor, if you want HP.

Dwight

[Chaplin]

Barry-
Do you know what month's issue the article will be published?

[wrench87]

i made 343 rwhp and 322 rear wheel tourque with my 342 tuned with the pms
i have always been unhappy with the lack of tourque feel, other then that the motor runs great idles well good in traffic,m runs cool. but it is not a big block i just want the right look under the hood and more tourque.

barry when is that article coming out?.

[Barry_R]

No idea when the article will run yet. I can tell you that Jay got the whole project finished for under $6000 retail including two cans of spray paint...

Chase me down on the phone 248-931-0358 and I'll run the combination for you - I just cannot post the data publicly as a courtesy to the magazine folks.

[wrench87]

how would this engine behave on the street what would it idle at and what would it rev to? if i went from the 4.250 stroke to the 4.125 what would the difference be in hp and tourque? would you suggest arp studs or just the arp bolts for heads and mains, are windage trays neccessary for the street would i benifit if one was used?.

[Barry_R]

I consider the windage tray a must - not for any horsepower gain, but for improved oil control.

The ARP bolts are a nice upgrade - although I've never seen a factory FE bolt fail in service - they are all 40 years old and normally look kinda ratty. Studs are not needed at this level - again a nice upgrade - but not needed.

The cam in the test motor is pretty snotty and would be a lot of fun on the street as long as you are happy with a 900+RPM rumpity idle. You could tame it a step or two and still keep most of the power.

The 4.125 stroke version would give up ROUGHLY 35 horsepower & TQ

[RICK LAKE]

wrench87 I just got back from Run&Gun with my car. The motor has a stroker kit from Barry R. That works great. 4.25 bore and stroke with 10.2 - 1 compression. I am running a small roller crane cam(hydro) I have not had time to get back to the dyno guy for a tuneup. By the seat of the pants I am guessing another 50-60-tork and about 70-80 ft of torque. This is from 368 hp & 466ft. Car is smoking the tires in 2nd and 3rd (racing auto cross). Build a stroker motor. If you can get a 4.25 crank with BBC rods in it, DO IT. Dont worry about 500HP. Torque moves the car, not HP. 6,500 rpm limit. Barry's kit bolted right in the shelby block with no problem. Breakin was Good. Will get the car to the dyno in a couple of weeks for a tuneup. The cam is 587-607" and has a nice idle. The extra 57 cubes help also, from 427 to 482. I got a hydro roller cam from KCR, this is for my next motor, a 496 with a larger stroke and small bore. The best thing I can say is build the 390 to what you want or can aford. Get a trans and rearend ratios to match the power range in the motor. If you are going racing, stay with the small blocks, they are cheaper to run and make more power per cube than a FE motor without 20 grand worth of work. Windage tray a must, I have a canton one. It will need to be modified for a stroker motor. ARP the whole motor and follow the instructions for stretch bolts on the rods. The 4.25 to 4.125 loss of power would be about 15-18 hp and 30-35ft of tork. Rick Lake