what 360 block to use for 800+ turbocharged hp

[Way2QWK]

Ive been away from the Mopar scene for 6 months now. Im doing a complete rebuild of my Challenger. It will continue to sit for at least a year or so, until I finish my other projects.

I had intentions of doing a nitrous 600hp 360 but Im sick of carbs and nitrous so.....

I want to build a Fuel injected turbocharged motor making around 800 reliable hp. This will be at least 2-3yr project

It needs to be streetable- racegas is fine

single or twin turbo?
What engine block will be required for this hp goal

I have knowledge with F.I. and turbos .I have a 10 sec TurboBuick

Any opinions on the best approach to this??

[dewme5]

I've been checking out just this same thing. I like the "R" block, all except for the fact that there are still only 4 head bolts per cylinder. That, I don't like at all. So, I keep checking musclemotorsports.com to see if I can find any used race blocks for cheap.. Mopar wants almost $6000 for the deep skirt aluminum block with 6 head bolts. Other wise, it's going to have to be a B block that ends up in my car. I know you can get a 4 bolt block to seal a head gasket, but 5 and 6 head bolts are much better suited for bigger power/boost.

[turbododge]

At 800hp you are going to need quite a bit of boost 20+psi and some rpm to do it. You will most likely be limited in the compression you can run at those boost levels, unless you use water/alcohol injection. An R block is probably the way to go-they are 6 bolt heads, but it will be spendy as these are setup for all race parts, dry sump etc. You should be able to make it streetable, but it won't be real docile.

[dewme5]

looking at the picture of the r block in the mopar perf. catalog only shows 4 head bolts. ??

[turbododge]

I am looking at page 101 of the new MP book at the R3 blocks. They say 6 bolts and appear to have added the two extra at the top and bottom of head surface. Wouldn't do much for the between the cylinder blowouts that I would get.

[dwc43]

You'll have to have the block cut for o rings just like the top fuel cars and the like use. You will need arp head studs along with studs for everything else you'll be using. Remember that when you change from main bolts to studs you will have to line bore the block again and you can't put the studs in the rear main. Want clear the oil pump.

[Way2QWK]

Is a stock block good to about 600hp and no more

[dewme5]

ahh.. I don't have the new mopar book, I have one from 99. and it's just the R block, not R3 block that I was seeing.

True though, it won't cure the blowout problem. the 2 added bolts aren't going to change the spacing of all the bolts. that would require a whole new bolt pattern. something i didn't really think to much about until looking at the $6000 alum. race block (because that's the only 6 bolt small block pic I have). Sort of kills my plans for a big inch small block. so I'll just do the big inch small big block.

I don't mind o-ringing the block, but I want to stay away from copper gaskets.

[brian phillips]

Pertaining to the 4 bolts per cylinder the turbo supra's at over 30 psi of boost use them. O-ringing should definetly help. With a very eficient turbo (BIG t-72 single or a pair of 60-1's) 800 Hp should be available at 15-16 lbs of boost. The top end will need to have good flowing heads and vey good tuning. Definetly use a high gear ratio to help load the turbo and build boost quicker. The bigger the motor the better also.

[brian phillips]

also at those boost levels a larger efficient intercooler will be required.

You say you want a street car, but race gas is fine. Sounds more like a race car on the street. The wonderful thing about boost is the ability to be very docile then wild when you want it.

[dwc43]

The big tubos will make it loose bottom end though. Plus it will create a lot of turbo lag as well. Better to stay in the middle on the turbo sizes.

[Robthaham]

I guess it really depends on how far you are willing to go with the turbos and how much designing of your own parts. There has been an idea rarely seen in the turbo world of turboing a turbo. Two small turbos one running the other produces lots of boost with a mild amount of exhaust, but then you have to worry about the blow out. As for the engine and how to seal the heads to the block, get the rings cut and find the sturdiest block you can find in iron not aluminum. Aluminum may be light, but it is not as strong. For an 800hp 360 you have your work cut out for you.

Good luck!!

[dwc43]

Aluminum is per pound stronger than cast iron. Just look at those 7000 hp blown and injected Keith Black Hemi's on any NHRA or IHRA rails and funny cars. It's much better than cast,but more exspensive. Indy sells 800 and 1000 hp dual carb engines for about 17,000, so I know they are stronger and the way to go no matter what.

[turbododge]

As was said, an 800 hp small block is going to be very weak at the low end, depending on how you do it. If you get your hp by running high rpm, the low end will be very bad, but you will need a little less boost. If you do it at lower rpm and very high boost, you get all kinds of other problems because of the high boost. Either way, you are going to sacrifice a bunch of streetability going that high. A 600 hp small block can be done at 15 psi 5500 rpm, on pump gas, and be very docile on the street, with good throttle response. It is still a lot of power for the street, and will live a long time. It all depends on what you want to use the car for.

I wouldn't be afraid of the copper gaskets and o-rings. If done correctly, they work very well. I have had them in the TT340 for over 14 years without any problems at all.

[brian phillips]

turbodoge, I have been pondering running copper gaskets with o-rings. If I run a .080 gasket I will lower my comp. down to abou 9.2 to 1. I would like to try this before I opened up my edelbrock heads to open chamber. My question is would I need to run receiver grooves in the block.

I found a company on line that mostly does magnum motors and they run composite gasket with a o-ringed head. the o-ring rides right outside the fire ring. If I could get a gasket that was thick enough I wouldn't mind trying that. I will probably call them after the holidays.

My other option is to run my openchamber steel heads to lower my com. but my edelbrocks alone are probably worth 75 hp. Also the heat absorption of the aluminum should help keep detonation away.

The site I believe was KLR or something like that ( if you look up o-ring heads on google it is one of the first in line) They say the large head bolt hole spacing allows usually about 8psi before blowing out. Usually towards the lifter valley.

Been out of town for a week and ready to get back on the cuda. Thanks.

[sanborn]

I suggest the R3 block be used. It has thicker cylinder walls(safe to 4.200"), less bore just give more wall thickness and a more rigid block. Head gasket failure usually is attributed to block flex. The R3 has a very thick deck(about 1.00") added iron on the front of the block, and thicker pan rails. I wouldn't use the 9.00" deck, use the 9.20" or the 9.58"(but the 9.58" just requires a heavier piston). The extra two 3/8" bolts per cylinder won't hurt.

For the cylinder heads, I suggest the W7 or W8s. Go on and take advantage of newer raised port technology. Don't use the W9s, the deck isn't as thick. And of course, all have the extra head bolts. I wouldn't O-ring the block, I would machine receiver grooves in the head for the stainless ring in the gasket. That technology has been around a long time and frankly, works better than O-Rings.

Don't know how a turbo affects the combustion chamber pressures/block flex; but, at higher RPMs the flex shouldn't be too bad. R block, W7,8 and 9 engines run 16 to 1 and up every day, so do the aluminum block, W9 headed engines. And both produce 800HP! I think you would be OK!

[sanborn]

One other thing, I noticed your reference to aluminum blocks. My advice is stay away from them unless:
1. You want to run a dry sump system-they have no provision for wet sump.
2. They have no provision for water entry and front covers to mount belt driven pumps are custom fabricated-either GM or Mopar race pumps only.
3. Motor mounts are early GM, and you must use a mid engine plate.
4. Standard bearings don't work without alteration.
5. You can only use a roller camshaft.
6. Block growth would be a pain on lifter clearances for street use.

BTW, the R5/P7 Nascar engine has the same problems as the aluminum block. But, at least the R5/P7 engines have a provision for mechanical fuel pumps, the aluminum block does not.

The R block is your best bet-But make sure the shop that does your work has a deck plate for the 18 head bolts!!!