is a dss racing shortblock any better than a stock one?

[70torino429]

i know there are other aftermarket engine blocks like the dart and boss blocks but came across the dss racing bare block. now for the questions. the one featured in jegs right now is a level 20 which is supposedly the best one they have. is that any stronger than a stock 302 block ill be pulling out of the 90 crown vic? im going to be building a 347 stroker and was wanting to know that ill have some bottom end strength. only things ive really been able to find out is that the level 20 block has thread in freeze plugs. the level 20 block costs just under a grand. so is this a good option? or would a stock 302 block with main and valley girdles be ok for what im doing. projected horsepower is going to be in the 400-450 range naturally aspirated, but i am getting some desktop dyno runs to get a better estimate where the hp will be. i do have more questions on this engine build but was curious about the block first.

[70torino429]

heres what desktop dyno came up with for my combo. gained 8hp from this run im posting when switching from 1.6 roller rockers to 1.7 roller rockers

[mrltd]

valley girdles...lol.

The DSS level 20 is still a production roller 302 block from what I've read on thier site.

Are you building a 7000 rpm motor? What are the Hp goals?

[70torino429]

i doubt the motor will ever go over 6000 rpm, it is going into a big ole crown vic by the way. id like to be around 400hp and 450tq. that run on desktop dyno shows im actually a little above that with my projected setup at almost 500 tq. will i be safe with a main girdle? the stroker kit im planning to buy has hypereutectic pistons and a cast steel crank, so i was curious if theyd hold up over time since i want this engine to last. the stroker kit says its "perfect" for 500hp applications naturally aspirated.

[mrltd]

I guess if the block is completely machined and ready to go it's not a bad price, you'll spend that in machine work on your block anyway. The DD you posted peaks at 5K, so I'd imagine a stock block would be OK, though like always it's the weakest link.

This is pirate or mercracer territory.

[70torino429]

maybe pirate or mercracer will chime in, but i am deffinately going with this motor. i suppose someone is going to have to help me out on what parts in the trans to upgrade and what torque converter, since the trans needs to be replaced anyways and ill have it out and apart. this is going to be a daily driver somewhat. i think i might stick with the stock block and have it cleaned up locally instead of ordering something from god knows where. i know someone with a similar build but they are running a little bit less compression and smaller heads, theyre also running a carb and ill be going efi. ive already got the bulk of research completed on this but still need a few more details and specifics before i start writing checks out to summit. i do need to find what the best intake that is reversible is.

[1987cp]

What are the parts you have planned for this thing? I'd much sooner build a 351 than go to the hassle and expense of a stroker.

[Mercmarquis]

347 will always make more power than a 351 with a simmilar build... Parastatic loses because of the larger journals in a 351 as well a small wieght disadvantage amoung other things.

Honestly I would build a 383 stroker out of a 351 block... Can be done on the cheap and the 351 blocks are good to around 650 hp with no more than 6500 rpm I've heard. Is there a reason you are limiting yourself to a 5.0 block? 383 stroker will make more power for less cash and will handle 500hp all day long on a stock block.

[Pirate]

Here is my advice:

You are building the wrong motor for this car.

Concerning 347's: This is a drag strip engine, not something for a street car. They really aren't any good for endurance racing, either. They produce a lot of power, but the problem is that a 347 (based on a 4.00" bore block) has a few problems; first, you have a crappy rod-stroke ratio, causing side-loading issues with the pistons; second, you have a really short piston that you're yanking side to side, so the pistons don't last very long....you can expect maybe 60K-100K out of this engine before it's time to have to go through it again, if the main webs don't go first.

The 347, for all intents and purposes, in a stock block, is just a little too much mail for the stock envelope.

If it were my engine?

If I absolutely had to stick with a 302-based block....the biggest setup I'd go with would be a 331. Preferably, if I was stuck with a stock 302 block no matter what, my ultimate street setup would be a long-rod 302, AFR heads, and a supercharger of some sort. The short block would be incredibly reliable, and it should last quite a while.

Or, to keep it simple....go with a 351W, and get the absolute lightest connecting rods and pistons available, as most 351W replacement slugs are freaking heavy.

You also have the option of doing a 351W on the cheap with a 393, which can use 302 pistons (which have at least a 22CC dish or so), stock 351W rods, and the 393 crank.

Problem Solved.

[70torino429]

What are the parts you have planned for this thing?

id build a 351 based engine if it was for a truck. plus i already have a good 302 block to start with. planned parts are, afr 185 heads, e303 or similar cam, 30lb injectors with matching calibrated pro-m air meter, 75mm tb with matching egr spacer, bbk shorty headers, 2.25 true dual exhaust with high flow cats (will this be enough exhaust?) flattop pistons, and eagle cast steel crank with forged i beam 5.400 rods, main girdle and windage tray. im not sure what intake im going to go with yet as im still trying to find out what the best intake is that can be flipped. im going to try out 1.6 and 1.7 roller rockers to see how it runs with each and choose what i like best. im probably forgetting a couple things but thats a rough idea what i have planned.

347 will always make more power than a 351 with a simmilar build... Parastatic loses because of the larger journals in a 351 as well a small wieght disadvantage amoung other things.

Honestly I would build a 383 stroker out of a 351 block... Can be done on the cheap and the 351 blocks are good to around 650 hp with no more than 6500 rpm I've heard. Is there a reason you are limiting yourself to a 5.0 block? 383 stroker will make more power for less cash and will handle 500hp all day long on a stock block.

a 351 based stroker will suck out alot more gas than a 347. so in my mind its a bit of daily driveability reasons and the fact i already have a good 302 block to start with. granted a 347 isnt going to get great mpgs but it would be better than a 351 based stroker. if the 302 block ends up crapping out on me then ill go with a dart block next time around but i think im going to try this block with a main girdle and upgraded arp hardware all around. hopefully i wont run into the oil control problems ive heard some people having with the 347s. also are hypereutectic pistons and the eagle cast steel crank going to work as long as i dont add any nitrous or supercharge it? the compression ratio is going to be right around 10.5:1 so i should be able to run 93 octane pump gas in it without trouble.

so, what should i be doing to the trans and driveline to hold back this kind of power? as well as what torque converter?

[70torino429]

Here is my advice:

You are building the wrong motor for this car.

first, you have a crappy rod-stroke ratio, causing side-loading issues with the pistons; second, you have a really short piston that you're yanking side to side, so the pistons don't last very long....you can expect maybe 60K-100K out of this engine before it's time to have to go through it again, if the main webs don't go first.


If it were my engine?

If I absolutely had to stick with a 302-based block....the biggest setup I'd go with would be a 331. Preferably, if I was stuck with a stock 302 block no matter what, my ultimate street setup would be a long-rod 302, AFR heads, and a supercharger of some sort. The short block would be incredibly reliable, and it should last quite a while.



Problem Solved.

the 347 actually has the same rod/stroke ratio as a 300 inline 6 ford engine so that is a non issue in my book as i dont think anyone would question the ford straight six reliability. the smaller piston on the other hand is a weak point in almost all stroker motors. if i get 100k miles out of it ill be satisfied, im not sure how much longer a 331 would last anyhow?

if something does go wrong with it or im not happy with the results i may go with a 331 when its time to rebuild, but at least ill have a nice top end to put on to a 331 already. ive seen a few 347s go over 100k miles so it seems like its all in how well you build it. it seems like the only real issue is the oil control problems due to the piston pins relative position to the oil control ring, which if you setup the engine properly, again shouldnt be an issue. and technically the engine is only going to be a 342 since the block isnt getting bored .030 over.

in my opinion for a street car i dont need a 351 based stroker like a 393. if it were a truck on the other hand that might be another story.

[1987cp]

a 351 based stroker will suck out alot more gas than a 347.

How's that the case?

[70torino429]

a 393 vs a 347. i think its as simple as more cubic inches needs more air and fuel. it may not be a ridiculous amount more but it will be more.

[1987cp]

Whoops, I missed the "stroker" part.

[mrltd]

you know, doing a stock displacement with a decent topend will be a lot cheaper, and not cost you that much HP...