Which is cheaper & more reliable SC331ci or N/A 408ci

[deadly97snake]

Well in the past few months while I've been on deployment, I've been asking questions about a 500hp 408ci engine. My plan was to have a N/A 408 w/ AFR 205 heads, a custon cam,and a intake to match it all(TFS-R 351, Victor 351, or a Spyder Vic Jr). I've been saying I want to keep the A/C and power steering and be able to do 10's w/ slicks in the 1/4.

But lately I've been seeing alot of guys in here with Supercharged 331ci engines & AFR 185 heads with the same amount of HP. So I wanna know which is cheaper & more reliable? The supercharged 331 or the N/A 408ci?

 

[94Five0]

i'm gonna say 331. frist off because its pretty sane, to the untrained eye its appears to be another 5.0 you'll get decent gas milage an its livable day to day..any efi' big block is gonna be murder as far as drivability. buddy of mine built a 331 an threw on a small turbo.. makes about 650 rwhp... another guy i know has a 347 an threw a compucar 200 nitrous shot on it.. it runs 9's... unless its a carbed dragster.. stay efi an go with a nice stroker. you wanna go big, but sane check out 351's.

 

[Joes95GT]

If you want to run 10's, build a 331 with AFR 205's and a Victor 5.0 intake and a hydraulic roller cam for the broader torque curve. There are guys running low 10's in a 306, so it should be very do-able with a 331. A 331 cubes is very capable of running 10's, it's just a matter of the parts you choose to go with it. I'm a fan of N/A power, so if you want to go N/A I would go with the 408 over the blown 331.

BTW, a 351W is a small block, not a big block.

Joe

 

[94Five0]

BTW, a 351W is a small block, not a big block.

Joe

i meant big as in larger than a stock 302ci..not as in big block engine designation..

 

[ponyboy19]

well if you are willing to use a stock roller block 351 and do a budget internal build with 10.5:1 compression 408 then I would go that route. it will make a very streetable 550 fwhp and the block would be solid at that level. but it wouldn't leave much room for a power adder with that block.. 650-700 would probably be it with a girdle IMO. but then again a 10 second blown 331 needs more then a stock block IMO anyways.. overall I think you could do a budget 408w and make great power and hit high 10's for less considering you wouldn't need a blower and as much tuning as you would with a 331 blown set up. like any build it's all about how fast you want to go and how much your willing to spend to be "safe".. you could do a budget build for 45-6000 complete or you could do a killer build for $15,000 all what you want to spend

 

[ChewiesDad]

I agree, and I think the 408 N/A will be more reliable.

 

[moneypit94]

this is very interesting thread, for i have a blown 331 and i also have an blown EFI 418 on the way. Well i think the blower is a little overkill especially with the 10.5:1 pistons it has so i have been thinking about going NA with it.

BTW it dynoed right at 775 fwhp with like 4 lbs of boost...

EDIT: After thinking about it i emailed the guy who I bought the motor off of and he said that they detuned it to 4 lbs after they dynoed it... I thought that 775 was a little high for 4 lbs of boost... He said it was like 12-14 lbs... I emagine with 4 lbs it would be about 570 ish fwhp...

 

[deadly97snake]

overall I think you could do a budget 408w and make great power and hit high 10's for less considering you wouldn't need a blower and as much tuning as you would with a 331 blown set up. like any build it's all about how fast you want to go and how much your willing to spend to be "safe".. you could do a budget build for 45-6000 complete or you could do a killer build for $15,000 all what you want to spend

But with a "budget build" would it be very reliable? With only spending like 6k with it be "safe" at all? With a 15K "killer build" will it be much faster than 10's or will it just be "safer"?

BTW it dynoed right at 775 fwhp with like 4 lbs of boost...

and thats all I have to say about that

i'm gonna say 331. first off because its pretty sane, to the untrained eye its appears to be another 5.0 you'll get decent gas milage an its livable day to day..any efi' big block is gonna be murder as far as drivability...

So the 331 will be more driveable? How so? The gas milage will be better too? By how much?

 

[ChewiesDad]

Look at it this way:
If your goal is say, 500 horsepower, a 408 can make that while only pushing 1.23 horsepower per cubic inch. That's like asking our 302's to make 360 horsepower. Not all THAT demanding I don't think. But for the same 500 horses from a 331, it would add up to 1.51 horses per inch. That's like pushing 456hp from a 302. AND you'd have the pressure of a blower on top of that. The 408 wouldn't need a forged crank and wouldn't rev as high as the 331.
No boost, less HP per cubic inch, same goal. I think the 408 would be more efficient, more reliable, and cheaper to build.
Just take into account all the external parts you need for the swap to the different block.

 

[ponyboy19]

But with a "budget build" would it be very reliable? With only spending like 6k with it be "safe" at all? With a 15K "killer build" will it be much faster than 10's or will it just be "safer"?

Yes it would be extreamly reliable at 5-550 fwhp. Show me stock 302 block 331 that can say it's extreamly reliable at 550 hp.. even with a girdle at that much power a stock 302 block is on the edge of borrowed time IMO. and an R or Dart block just added about 2000 to the motor. A stock 351w block I've been told is solid for 6-700 fwhp, the sportman 351w is good for 850-900 and the Dart 351w is well awesome. So if I were doing a budget build I would look for a roller 351w block clean it up and install a cast crank, I or H beam rods, and good hyperetic or forged pistons and install it. with a set of AFR 205 heads or possibly 225 if your going to run a 10.5-11:1, a good hydrolic roller cam, 1 3/4-1 7/8 long tube, 90mm throttle body, 92mm maf, and a good intake like a spyder, 351 TFS R with the 90mm opening, or a victor 5.8 EFI this motor will make a ton of streetable N/A power and not have the hassels of a blower, If you really want to build on a budget you could do a 393 as well. You only need 302 pistons and 351 rods, plus a 3.85 crank. you can get the cranks pretty reasonable. .
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33616&item=2458803298

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33616&item=2458915079

If your going to buy a rotating assembly kit then I would stick to the 408 since they are pretty much the same price

Do some research, talk to some people who own them. I personally plan on a N/A fuel injected all forged Dart block 9:1 408 with Pro 1 225 cc heads which I'm probably going to order in the next couple weeks from Bennett Racing. they say it will go 580 ish FWHP N/A and make crazy power when i add a blower later on. If I were to bump the compression up it would probably go 625+ fwhp n/a so that gives you an idea of what these motors can do. and thats with a custom hydrolic roller cam with a 67-6800 rpm shift point. The only reason I'm considering a Dart block over the sportman in my situation is because I plan on boosting it to 800+ fwhp. And I'm willing to pay for reliablilty and added safety. but then again I haven't placed the order yet either IMO there really is no replacement for displacement and 500-525 fwhp shouldn't be any issue at all even with a "mild" set up.

 

[deadly97snake]

Yes it would be extreamly reliable at 5-550 fwhp. A stock 351w block I've been told is solid for 6-700 fwhp, So if I were doing a budget build I would look for a roller 351w block clean it up and install a cast crank, I or H beam rods, and good hyperetic or forged pistons and install it. with a set of AFR 205 heads or possibly 225 if your going to run a 10.5-11:1, a good hydrolic roller cam, 1 3/4-1 7/8 long tube, 90mm throttle body, 92mm maf, and a good intake like a spyder, 351 TFS R with the 90mm opening, or a victor 5.8 EFI this motor will make a ton of streetable N/A power and not have the hassels of a blower,

Do some research, talk to some people who own them. IMO there really is no replacement for displacement and 500-525 fwhp shouldn't be any issue at all even with a "mild" set up.

Thats great.

Does anybody else wanna throw in there $.02???

 

[Black70Fastback]

well one, im an N/A freak. and like the other guy said, 500 out af a 408 is asking for less than 500 out of a boosted 331 and theorietically have less stress. i think the 408 would be cheaper to build due to the cost of a supercharger. plus haveing the 408 never outrules the addition of a supercharger farther on down the road!!

someone who says technology replaces displacement never put technology ON displacement.

 

[deadly97snake]

So if I were doing a budget build I would look for a roller 351w block clean it up and install a cast crank, I or H beam rods, and good hyperetic or forged pistons and install it. with a set of AFR 205 heads or possibly 225 if your going to run a 10.5-11:1, a good hydrolic roller cam, 1 3/4-1 7/8 long tube, 90mm throttle body, 92mm maf, and a good intake like a spyder, 351 TFS R with the 90mm opening, or a victor 5.8 EFI this motor will make a ton of streetable N/A power....

A 90mm throttle body and a 92mm maf? Isn't that a little too big? I was being told somewhere around an 80mm TB and a 80mm maf. I don't want to go too big or too small.

Also if I did go with the 80mm stuff would I still want the TFS R intake with the 90mm opening?

A third question, I was looking at the acufab longtbe headers. What size should the collector be? 3in. or 3 1/2?

Thanks stangnet

 

[stangboy]

Accufab makes headers?????

 

[ponyboy19]

IMO no.. on a nicely done 408 ci motor a 90mm throttle body is what everyone from people who have them to builders are telling me to go with. If you were to use milder heads like 185's, twisted wedge or what ever I may go with an 80mm but with a set of afr 205cc or 225cc heads and an aggressive cam I'd probably stick with the 90mm throttle body and matching MAF. that's my opinion and to be honest i think the difference in hp would be minimun depending on cam selection, rpms, and power output. Regardless I would stay with an intake with a 90mm throttle body. 75mm openings and throttle bodies are not big enough for a motor of that size that is cabable of that much power. 80 mm t/b is minimum. and you don't want that on an intake with a 75mm opening. as far as headers go. if you use the 205cc heads you can use a 1 3/4 long tube with 3" collector from Mac or who ever you want that has a swap header in that size. 3" collectors should be plenty on a N/A 408 IMO. if you use a 225cc head then you have to use a 1 7/8 header to fit the port and they are a bit more expensive when you start talking acufab and kooks.

 

[ponyboy19]

Accufab makes headers?????

http://www.accufabracing.com/exhaust.htm#HeadBolts

 

[deadly97snake]

If you were to use milder heads like 185's, twisted wedge or what ever I may go with an 80mm but with a set of afr 205cc or 225cc heads and an aggressive cam I'd probably stick with the 90mm throttle body and matching MAF. that's my opinion and to be honest i think the difference in hp would be minimun depending on cam selection, rpms, and power output. Regardless I would stay with an intake with a 90mm throttle body. 75mm openings and throttle bodies are not big enough for a motor of that size that is cabable of that much power. 80 mm t/b is minimum. and you don't want that on an intake with a 75mm opening.

Ok, I've been looking for a couple of days and I can't find anyone that sells a 90/92mm MAF. The only ones I can find are for the new lightnings. Can anyone help he on this. I think Pro-M makes them so I went on there website but I couldn't find them. Will the lightning MAF's work? Also When I look at these I want them to match my injector sizes(42lb) right?

 

[ponyboy19]

Here is a link to the Pro M 92mm. I've also heard that the Pro M 83mm will work nicely as well and is actually the largest allowed in some race classes. Personally if it's not a class specific car i'd just use the 92mm.

http://www.pro-flow.com/Pro-M meter_Gallery.htm

Here is a link to the prices.. the 92mm is 425 from pro m but you can probably find it a bit cheaper through a different company that sells the Pro-M's.. just have them calibrate it for your injectors.. you can choose.

http://pro-flow.com/Price Dealer Order/pricelist2003.htm

not sure on the LMA. If you call Jim or one of the sales techs at Pro-M they will help you out with your set up. I like the idea of keeping the induction track the same size hence the 90mm throttle body 92mm maf and 4" tubing.

 

[deadly97snake]

Here is a link to the Pro M 92mm. I've also heard that the Pro M 83mm will work nicely as well and is actually the largest allowed in some race classes. Personally if it's not a class specific car i'd just use the 92mm.

http://www.pro-flow.com/Pro-M meter_Gallery.htm

Here is a link to the prices.. the 92mm is 425 from pro m but you can probably find it a bit cheaper through a different company that sells the Pro-M's.. just have them calibrate it for your injectors.. you can choose.

http://pro-flow.com/Price Dealer Order/pricelist2003.htm

not sure on the LMA. If you call Jim or one of the sales techs at Pro-M they will help you out with your set up. I like the idea of keeping the induction track the same size hence the 90mm throttle body 92mm maf and 4" tubing.

Thanks for going out of your way and helping me out. I know I will have more questions in the near future.