How much power can a 351W block handle?

IndyBlk5.0 · May 26, 2004

This block is out of a 69 mach 1 with 4 barrel carb.
It will be main supported, windage trayed, forged internals all arp bolts blah blah.
I want to know about how much power this block can handle safely.
Thanks.

cougar694u · May 26, 2004

Ummmm, the 351W wasn't made until 1969, but that's okay, same casting up to like 86 or something. Mine's putting out roughly around 500hp at the flywheel, and I don't have the windage try, main support, or a forged crank. It's got plenty of potential...

IndyBlk5.0 · May 26, 2004

sorry, he said late 60's fastback, so i threw out a number.

Im aiming for atleast 550rwhp under boost.

cougar694u · May 26, 2004

Should be no problem with the main support and forged internals. Mine is a 69 block with dart sr's, running 11.5:1, victor jr and a cam that I wish was better, but it's supposedly good to around 7200 RPM (lifter float) from the balance sheet. If you're turning high RPM's with strong spring tension, throw in a set of rocker girdles as well. If it will be race only, possibly look into having the block cemented, you'd be fine for like 1000+ crank hp, but it won't cool as easy.

IndyBlk5.0 · May 26, 2004

What heads were on that motor stock?
He has them, I think I might have them ported out a lot. Is it worth it?
Ported very well, what would they compare to? 205's? 225's?
Its going to be EFI. Possibly daily driven. Probably supercharged.

cougar694u · May 26, 2004

Unfortunately, I had the 2v heads, not the 4v heads. Supposedly, the dart sr's are the 4v cast. If they're the 2v (had a 2 barrel carb on it stock, which most did), I wouldn't mess with it. If they're the 69 4v heads, they're supposedly the best heads, and use the big spark plugs. I have a set of GT-40 P's with a fresh valve job and good springs for like .530" lift that are set up for the 351W (the head studs are bigger, so I had them drilled) if you're interested. They utilize long reach plugs so the electrode is in the center of the cylinder. If you're going blown, are you going to run mildly above stock compression? GT-40 P's don't like dome pistons because of the long reach plugs, they would have hit my 0.150" dome pistons.

IndyBlk5.0 · May 26, 2004

probably 8.5:1 compression...
Any way to tell what heads they are?

cougar694u · May 26, 2004

Look up the cast number and do some research. Other than that, I'm not really sure. You could look at the size of the ports, but if you don't have a basis for comparison, that won't do you any good.

IndyBlk5.0 · May 26, 2004

He said they are the stock 351W heads for the Mach 1 4 barrel.
Does that tell you anything?

IndyBlk5.0 · May 26, 2004

Can anyone else help me out?

5.0 HOtrain · May 26, 2004

Stroke that pig and leave it n/a, 550rwhp is doable with the right parts and budget n/a. My 418 made 581/539 flywheel. 69 block, all forged internals, girdle, hardblocked up to waterpump, TFS "R" heads, super victor intake, 1000cfm demon, custom cam, 1 7/8 kooks, ect.......... Hydro roller, box stock parts, PUMP gas. Just me.
mike.

408stroker5.0 · May 26, 2004

A 69' Block WITH a good quality stud girdle and forged internal's will handle 700HP pretty easily, with no worry's. Anything above that is starting to push it a bit, but is do able. Fill the block (if not used on the street) and that will up the rating abit. The 69' Head's are definetly better than later W head's as the port's are a little larger and same with the valves(I can't remember the specific size) Basically the later head's were all smoged up. If you want to make any decent power though you will have to go to an aftermarket head for sure (AFR, Dart, Edelbrock etc.) No matter how much porting/polishing is done on them they won't even come close to a 205. I recomend investing in some AFR 205's. A little bit of money, but man do they perform. I love mine. The 69' W head's though work great on a mild 302 especially when ported and polished a bit, if a guy is on a budget and has them laying around.

I'd recomend going with a NA 408 or 418 Stroker setup (Check Sig.)
Pretty hard to beat a stroker these day's.

5.0 HOtrain · May 26, 2004

408stroker5.0, Do you have any track/dyno #'s for you're combo?
mike.

fwiw, I run the probe girdle as well, was happy with it, good quality.

drag79stang · May 26, 2004

I"m running a stock block (out of an 84 squad), in my car.
351W. Made 615hp @ 6400, and 555 ft lbs tq @ 5200 rpm.
Again, block is nothing special. Just paid real close to tolerances/machine work.
Been beating the living snot out of it for 4 years, and no problems whatsoever........

408stroker5.0 · May 26, 2004

5.0 HOtrain said:
408stroker5.0, Do you have any track/dyno #'s for you're combo?
mike.

fwiw, I run the probe girdle as well, was happy with it, good quality.

I just finished the car not long ago so I got no specs yet, but...... I'm booked on June 12 to be on a chassis dyno, so I'll have some RWHP/TQ number's soon. As for track time's, I'll be on the track most likely in July, as I wan't to fool around with my suspension (Mainly the front) a bit more before I hit the track.
When it come's to Flywheel power I'd estimate around 550HP and 545-560TQ. Your combo is a bit more radical than mine.
I was very happy with the probe girdle as well, except the ARP stud's they sent me were too short!!! I ended up ordering longer one's from ARP. Did you have that problem?
How does that 1000cfm Demon work for you??? Isn't that a bit too much carb?

Will post dyno/track number's soon.

5.0 HOtrain · May 26, 2004

The studs they sent me were ok? As far as the carb, I thought it was going to be too much. After alot of talk with Paul Krauss who did my machine work and dyno he talked me into it. It needed it on the dyno and being my first carb I wasnt going to question someone with years of experience. Dragstang, nice to see you on here again.
mike.

5.0 HOtrain · May 26, 2004

408stroker5.0 said:
Your combo is a bit more radical than mine.

.

Not really, I have a little more intake/carb. Similiar heads,ci, and compression. Whats you're cam specs? Mine are: 252/262@.05, 110 ls, .576/.576 lift w/1.6rr's.

Click to expand...

fawcett · May 26, 2004

Out of curiosity, what are you guys getting for gas milage? Are these gas prices making you wish you went with a smaller displacement motor?

More Cubes = Less MPG Right?

I guess what I am trying to understand is,
If a small block w/ power adder made the same HP/TQ as a large displacement motor, which would use more fuel on average daily drives through city/highway driving?

A silly question I know, but with pump prices like these it becomes more relevant to those paying for gas every 1-3 days in a daily driver.

Fawcett

408stroker5.0 · May 26, 2004

5.0 HOtrain said:
408stroker5.0 said:

Your combo is a bit more radical than mine.

.

Not really, I have a little more intake/carb. Similiar heads,ci, and compression. Whats you're cam specs? Mine are: 252/262@.05, 110 ls, .576/.576 lift w/1.6rr's.

Click to expand...

You got alot more duration than me.....
I'm using a Comp Xtreme Energy Hyd. Roller Grind 236/240@.050, .555/.576 lift w/1.6rr, 110ls
I could have went with more duration, but since this car see's ALOT of street and some highway time I decided not to go to radical. As for the lift, the original plan was to run 1.7 Rocker's but piston to valve clearence would not alow this, so I stuck with 1.6. Overall it work's like you woudn't believe with my combo and sound's F'n Awesome.
I combined this cam with Comp's new Bee Hive spring's & titanuim retainer's. (Ultra-light Set-up)Man, I would recomend those spring's to anyone. They sure helped bring the RPM cabability up on my 408, which is a hard thing to do with a Hyd. Roller engine.

Click to expand...

IndyBlk5.0 · May 26, 2004

Im set on a turbo 408. AFR 205's or 225's? Or maybe darts??????
I want 650 to the wheels, i should get there with low boost.

How much power can a 351W block handle?

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