Best small block for a cobra? - Page 3

BMK · #41 (**permalink**) 10-12-2004, 07:43 PM

brs94vette

I have a similiar motor. Car is well balanced (drivers not) and I have all the power I need. I have found any parts I have needed easy to get and reasonable priced...

After recently driving a big block Cobra I now understand the reasoning that Bondurant had in stating his preference for the 351 motor. Lighter and easier through corners/braking etc.

Bernie

Excaliber · #42 (**permalink**) 10-12-2004, 10:12 PM

I've been studying this compression ratio thing VERY closely lately. I'm going to reduce my 12.5 to about 9 something.

It seems that if ALL OTHER things are equal and ONLY the compression is reduced MY motor will loose about 150 horse power. Down from 667.

Kind of blew me away how important compression can be in developing high horse power. I'm pretty sure 500 plus will still be enough.

GeorgiaSnake · #43 (**permalink**) 10-13-2004, 06:07 AM

"Slick"

I was told that changing compression would make only a 2 -3% change in HP for each point of increase / decrease. I'm not sure who told me this - it seems low.

http://www.bgsoflex.com/crchange.html

300 HP with 9.5 to 1 - bumped to 10.5 to 1 = 307 +-

Randy

MidOHasp · #44 (**permalink**) 10-13-2004, 07:45 AM

Randy, the crank is the short one and set up to work with the needle bearings. Does your block have the extra bulge coming out of the endline rotary girder? If not, then it's not set up for the roller crank. You will need the J.P. Engineering roller crank retro-fit kit. It's worth it, though, IMHO.

DC COBRA · #45 (**permalink**) 10-13-2004, 08:52 AM

I RUN AN ALUMINUM 427 WINDSOR, DART 4.125 BORE BLOCK.427 CUBIC INCHES IN A BLOCK ASSEMBLY WITH THE WEIGHT OF A 302 SET-UP. 600 PLUS HORSEPOWER THAT WILL RUN ON PUMP GAS, WHAT MORE COULD YOU ASK FOR OUT OF A SMALL BLOCK.

DON

Excaliber · #46 (**permalink**) 10-13-2004, 10:27 AM

My source is George Anderson, owner Gessford Machine Shop. Recent award winner for the best machine shop in the Nation and FE expert.

HOWEVER, I don't think it's as simple as it may sound. For MY 427 FE at 100% volumetric efficiency and 12.5 to 1 C.R. the "math" indicates 600 plus horse at 6000 rpm. The dyno came up with 667 horse. Dropping THAT engines C.R. "mathmatically" reduced the horses by about 150.

Does that relation hold true for small blocks and engines under 400-500 horse? I don't know, perhaps not. BIG engines moving a LOT of air (intake/exhaust cfm ) are more sensitive to just about anything. My sidepipes drop a 100 horses off for instance. You couldn't say every Cobra looses a 100 horse from their sidepipes.

Ant · #47 (**permalink**) 10-16-2004, 04:52 PM

slick,

I reckon you must have mufflers/sidepipes that are very restrictive to loose 100hp over straight pipes.

The guys here that are getting similar hp to US engine builders, build mufflers that bring the decibels down to 95, with no real decrease in hp, this is all tested on the engine dyno

speedar · #48 (**permalink**) 10-19-2004, 10:25 PM

Its depends on your taste and budget.

Nup, Sorry Bevan but I think Chevy cobras have less value than Ford cobras, but in reality didn't Chevy say no to Shelby before he went to the blue oval?

Klayfish has got the idea in my book. Its all about power to weight in any motorsport.

If you can afford the dart block then you have some 427 authenticity without the weight.

I think the 351 is a good compromise but the cobra is only a middle weight that really doesnt need that broad shouldered torque curve. My 351C is moderate street and can't get traction in 1,2,&3rd and I havent even got 300bhp at the wheels

I suggest you build a screamer and go for a narrower torque curve A high reving build - probably windsor but some cleveland lovers will happily rev to 7500! You could go Clevor (boss) for better breathing combined with the smaller windsor journals but I think high flowing aftermarket heads are really the answer.

Spend the money on the Dyno2000 software and run various combos on the computer before you start to invest in your build. The software simulates dyno pulls and the quartermile and will identify weaknesses in your planned combo.

Ant · #49 (**permalink**) 10-20-2004, 12:20 AM

After many months of trying to sort out what size engine I will go for, I think I am on to it!
Bearing in mind going road racing is top priority, not drag racing or grunty road use!

331 because of reliability, rod ratio, SOUND/REVS. It will have to develop around 460-480bhp for my application.

Going to 347/355 is just lowering the rev range and reliability.
Heavier 351W blocks and the 393-427 loads up the drive train, reduces the handling, don't sound as good.
Big blocks are nice and have bulk torque etc, if I had the $$$ another FE but all alloy would be the ticket, or an all alloy 427 GM would be great eh - Bevan!

iwantacobra427 · #50 (**permalink**) 10-23-2004, 01:04 AM

What do you guys think of Ford's 5.8 Liter 392 stroker for less than $6,800? Is this a reliable motor?

StrokerCobra · #51 (**permalink**) 10-23-2004, 01:34 AM

What kind of guy are you? Enthusiast owner who loves tech, or want hassle free motoring or into big power?

That will hone down your choice. All motors have their strengths and weaknesses, nothing is a perfect combination in every respect.

Personally I love small Cleveland strokers because they are not your average Ford V8, and it takes a bit of know-how to get them to go really well. At full revs there's nothing like it.

If you want the most grunt with least hassles go BBC first choice and BBF 2nd choice.

I'm not a fan of the big stroker (408+) Windsors, for all the obvious reasons.

iwantacobra427 · #52 (**permalink**) 10-23-2004, 01:45 AM

I'll be doing a combination of highway cruising and blvd. light to light get up and go.. I heard as long as the 351 is not stroked to 427 it should be ok.. This Ford 392 stroker has 430 HP and 450 ft-lb torque. I definitely don't want a 500 HP + engine.. I want a engine that will give me hassle free miles and minimal tuning and mainteance. I'd like to only have to worry about basic maintenance once it's setup right.. oil changes, oil filter, spark plugs, timing, air/gas filters, etc.. I don't want to have to rebuild the damn thing every 12,000 miles.. or have oil leaking out the head gasket at 2,500 miles..

GeeDoubleYouSee · #53 (**permalink**) 10-23-2004, 01:59 AM

iwantacobra427,
Good for you iwantacobra427, hobbies are about yourself and every hobbyist tries to better the rest by more power and the right to say so. Just remember the city commity just got thru crushing a sports car in California "camero i think" No body i know could afford to watch their cobra being slaughtered like that not even if your well off.

I like the feeling I get driving my cobra, the weak 400bhp that mine put out is more than enough for the street and does ok on the 1/4 mile.

GWC

brs94vette · #54 (**permalink**) 10-23-2004, 08:04 AM

I'm going with the 392 Stroker. Plenty of HP and Torque for a 2500 lb. car. Brand new motor with warranty and Reg will back his work when he put's one in a BDR. I want him to deliver a turnkey car so I have one place to bring it back to with any problems.
Bruce

sirelesar · #55 (**permalink**) 10-23-2004, 08:09 AM

Bruce,
There is a guy on this list, Hal Copple, who has a 396w stroker, running 12.3's on street tires. Not only is his car nice and fast, he is one of the most elegant writers in here, and surely fun to read. You may want to look up his posts and see what he has done.
Darren

sirelesar · #56 (**permalink**) 10-23-2004, 08:13 AM

Bruce,
Just saw your post about hassle free driving, with moderate HP. Hal had put some serious mileage on his 396w.
Darren

chuckmynatt · #57 (**permalink**) 10-23-2004, 06:51 PM

Anything blue with the distributer located on the proper end (front).

Chuck

Aussie Mike · #58 (**permalink**) 10-24-2004, 04:43 AM

Quote:

Originally posted by chuckmynatt

Anything blue with the distributer located on the proper end (front).

Chuck

I've got a silver one with no distributor

Cheers

Rebel1 · #59 (**permalink**) 10-24-2004, 06:40 AM

The 393 windsor stroker has been a favorite for quite some time. However, I'm not all that keen on the version which uses the standard 351W rods.

There's also a 393 W kit from Scat with a 6.2 rod..that sounds interesting.

Another interesting stroker MAY be the 383 version available from Scat. It uses 6.25 rods on a 3.75" crank. This ends up a 1.66 rod ratio which I tend to favour a little.

Problem is...I don't know anyone who has one.

The 351 Windsor with alloy heads and water pump ends up as near as damnit to the weight of a 302 with steel heads and steel pump.

Nice to have all these options hey?

Badman · #60 (**permalink**) 10-24-2004, 07:57 AM

Just my two cents, but I have a 351W stroked to 408 in my Superformance. DSS Racing professionally built the engine with 475 plus horsepower and I believe it’s a great combination. The car is fast, agile and yet to be beaten.

Badman