347 or 408

stvneil · 03-05-2004, 07:58 PM

i am wanting to purchase a 347 or 408 carburated engine with 425+ h.p. it will be used with a c-4. anyone know where i can get a new or good used engine? it will go in a 79 capri.
thanks
neil

stang_racer20 · 03-05-2004, 08:11 PM

Are you talking about a fully assembled long block?
What kinda money are you looking to spend?
What kind of racing would you be doing?
Need some more info....

stvneil · 03-05-2004, 09:51 PM

i have been looking at longblocks (new) from $5500 to complete drop in's, balanced, blue printed dyno tested and broken in for $7500.00. would like to buy used for less. will be used for 80% street and 20% strip, any help would be appreciated.
thanks
neil

jonnyk · 03-06-2004, 12:44 AM

Remember you will need a new hood, headers, oil pan, and some other supporting hardware to do the 408.

If you can afford to do it, do it!

Scrapla · 03-06-2004, 11:13 AM

Yea the 408 would be better for racing app's but the 347 will produce some nice power and just drop in for that stealthy look.

soon2Bturbo · 03-06-2004, 11:51 AM

You must know a few facts first. 347's are not good for street driven stangs. The rod ratio is too big and will cause early ring wear (blow-by) and may even cause the cylinder bore to become elongated. Basically, there is too much side load on the piston and cyl wall since the piston travels too far down into the bore. Stick with a 331 if you want a 302 based block. Better yet, go with a 408. It will make way more power, and live a lot longer too. Yes you will have to buy diff headers, oil pan, motor mounts, etc. But you prob were going to buy new ones anyway, right. The cost difference is minimal. I suggest reading MM&FF March 2002 issue. Article is called "Stroker Ace" on page 104. It can explain much better than I can. Good luck. Make a wise decision so you only spend your $ once!

jonnyk · 03-06-2004, 12:50 PM

Quote:

Originally posted by soon2Bturbo
You must know a few facts first. 347's are not good for street driven stangs. The rod ratio is too big and will cause early ring wear (blow-by) and may even cause the cylinder bore to become elongated. Basically, there is too much side load on the piston and cyl wall since the piston travels too far down into the bore.

I suggest you don't contribute false information if you don't know what you are talking about. 347's are fine on the street...modern kits don't have any problems at all. Yes, there is more side loading on the pistons, but that isn't a very big deal in sub-6500 rpm applications anyway. You can also run tighter wall clearances with some of the new pistons out there and the thing will last a long time. The rod ratio isn't too big...nor is it too small. It's fine for street use.

420nitro · 03-06-2004, 06:04 PM

You know what, it all comes down to what you really want. Do you want stealth, then go with a 302 based motor.
If stealth is not that major of a concern then go with a 351 based motor. Don't get me wrong, you can if the funds are available, can even hide the 351 based motor under a stock hood. But all and all if it is between a 347 or a 408 I would go with a 408, hands down and never look back....And as a matter of fact that is what I did and have no regrets.
Now if you would have said a 331 then were talking about a different story. I believe a 331 is better than a 347. Better rod ratio and able to spin the motor faster easier. You really need to answer alot more personal questions like the ones mentioned earlier and like what if any power adders. If you plan on running power adders then a 302 based motor is not something I would recommend with out up grading the block. A 351 based motor can handle more power and include power adders for the same amount of money. Yes, you will most likley need a new hood,oil pan,headers and stuff but wont you want to replace them anyway???

If you already spent the money on those parts then stay a 302 base motor. If not then I would be looking at a 351 based motor.
Good luck with your project.
As goes for soon to be turbo maybe he just didn't explain it correctley. I understood what STBT meant and it wasn't all that off. Everyone on this forum writes a little different, so I can understand where he might have been coming from. A lot of times people seem to come off way off base but after a while you get what they were saying. Just ask questions on what they meant before blasting people, would be my advise
My 2 cents and dont give a shyte what others think

soon2Bturbo · 03-06-2004, 06:18 PM

Hey Jonnyboy, I don't like to insult people 'cause I think this forum is very helpful and useful. However, you run low 13's with a 331...ARE YOU KIDDING ME? Are you still using stock E7's. I don't care if you are at 2400 feet. You should be low,low 12's at worst. Maybe you're doing something wrong?

And you can't blame traction because your MPH is way off too. 8 years ago I ran a stock bottom end, ported E7's, stock intake, w/ a b-cam on radials and went 13.3 @ 104. And you have a 331? Now you tell me what's wrong with this picture? Sorry dude, I don't mean to make you feel like shiznit, but, YEAH I DO!!!

jonnyk · 03-06-2004, 06:25 PM

Say what you like. I have no illusions.
At my density altitude on that day (4200 foot air), my ET corrects to 12.65 @ 111 mph.

I don't blame traction, I run 17" street tires at the track, and won't be putting slicks on anytime soon.

I'm also running 8.4:1 compression with a small cam, with 1 3/4" longtubes. Very bad N/A combo. Very good blower combo.

I am looking to go above 125 mph in the 1/4 this year at altitude, which isn't easy no matter what size your engine is.

Considering a brand new 405 horse ZO6 went 13.27 @ 107 mph on the same day I was at the track, I don't feel my times are all that bad. I just wish I had the chance to line him up once

Also, a Procharged 2001 GT went 13.48 @ 110 mph the same day I was there. He had the extra oomph from that intercooler, but it didn't matter much on the launch pad

If you think 2400 feet doesn't make a difference, you obviously haven't tried it, let alone on a day with lousy air.

stvneil · 03-06-2004, 07:51 PM

thanks for all the replies. the 408 blocks ran $5500-$7500.00. since then i have considered a 331 for $3500.00. i would replace the oil pan and headers since i would want a 2 1/2-3" exhaust system. power adders, i don't know, but i hate to spend money twice. i haven't worked on car engines in 30 years and i am just gettin back in to this.
i have been running a stv boat with a 325 h.p. mercury engine. it is a 11 sec. 1/4 mile boat. i will be selling it soon and setting up this car to play with. i really don't know what i am doing so any help is appreciated. i do not want to spend a fortune on it, but i want something to hall ***.
thanks again
neil

jonnyk · 03-06-2004, 10:00 PM

Induction, heads, and the cam are everything. You can easily make a 331 run in the 11's all motor and have it very streetable as well.

soon2Bturbo · 03-08-2004, 12:32 AM

My apologies to jonnyk. I didn't know your combo was for forced induction. If I misinformed someone, then please correct me. However, there is a nice way to do it. I only get cocky when someone else gets cocky with me first. Anyway,too bad you couldn't have lined up with those guys, it would've been some good racin'.
To stvneil...If the 331 is more within your budget, then go with it. Either one will give you the power you're looking for. Especially if it's been a long time since you've had a fast car. I know 'cause I returned to the racing sceen after being out for 6 years. I thought my friends '03 cobra was the fastest car ever. Until I realized I just wasn't used to speed. Now it doesn't seem as fast as it used to. Good luck.

jonnyk · 03-08-2004, 10:28 AM

Quote:

Originally posted by soon2Bturbo
My apologies to jonnyk. I didn't know your combo was for forced induction. If I misinformed someone, then please correct me. However, there is a nice way to do it. I only get cocky when someone else gets cocky with me first. Anyway,too bad you couldn't have lined up with those guys, it would've been some good racin'.
To stvneil...If the 331 is more within your budget, then go with it. Either one will give you the power you're looking for. Especially if it's been a long time since you've had a fast car. I know 'cause I returned to the racing sceen after being out for 6 years. I thought my friends '03 cobra was the fastest car ever. Until I realized I just wasn't used to speed. Now it doesn't seem as fast as it used to. Good luck.

No hard feelings. I'll try to not come across so brash in the future when I am pointing things out...

fiveOguy20 · 03-14-2004, 08:00 PM

i agree its all in ur combo.. a 331 or 347 will run no faster than 302 if not part matched correctly. i've seen 347s run 14's soo lol.

with my old 347 combo i only gotta best of 12.5 at 110. but that was with Bcam an Y303 heads. i added X cam an plan on vic. jr. heads this year, so should improve.

03-05-2004, 07:58 PM	#1
stvneil Registered Member Join Date: Feb 2004 Location: baton rouge, la. Posts: 18	347 or 408 i am wanting to purchase a 347 or 408 carburated engine with 425+ h.p. it will be used with a c-4. anyone know where i can get a new or good used engine? it will go in a 79 capri. thanks neil

03-05-2004, 08:11 PM	#2
stang_racer20 Registered Member Join Date: Jun 2003 Location: Wisconsin Posts: 348	Are you talking about a fully assembled long block? What kinda money are you looking to spend? What kind of racing would you be doing? Need some more info.... __________________ 92 Mustang GT, 347 Stroker(Forged Steel Crank/Rods-Balanced, Forged Aluminum Dished Pistons), Trick Flow Track Heat Intake, Trick Flow Twisted Wedge Heads w/ Stage 3 port/polish, 80mm C&L MAF, FMS 30# Inj., BBK AFPR, Trick Flow Stage 2 Cam, Trick Flow 1.6R Rockers, BBK E.L. Headers, Flowmaster Cat-Back, MAC CAI, FMS Pulleys, Griffin Alum. Radiator, MSD Pro-Billet Distributor; AOD, Dynamic 3300 Lockup Converter, B & M Super Cooler, B&M Ratchet Shifter; 3:73 gears.

03-06-2004, 12:44 AM	#4
jonnyk Being stroked is great Join Date: Oct 1998 Location: Alberta, Canada Posts: 772	Remember you will need a new hood, headers, oil pan, and some other supporting hardware to do the 408. If you can afford to do it, do it! __________________ Novi 2000 now spinning off the snout of the 331... Mods Pics

03-06-2004, 11:13 AM	#5
Scrapla Registered Member Join Date: Apr 2002 Location: Florida Posts: 532	Yea the 408 would be better for racing app's but the 347 will produce some nice power and just drop in for that stealthy look. __________________ 90gt 347 and some bolt ons :-) RICE HATERS MEMBER #73

03-06-2004, 11:51 AM	#6
soon2Bturbo Registered Member Join Date: Jan 2004 Location: N. Illinois Posts: 15	You must know a few facts first. 347's are not good for street driven stangs. The rod ratio is too big and will cause early ring wear (blow-by) and may even cause the cylinder bore to become elongated. Basically, there is too much side load on the piston and cyl wall since the piston travels too far down into the bore. Stick with a 331 if you want a 302 based block. Better yet, go with a 408. It will make way more power, and live a lot longer too. Yes you will have to buy diff headers, oil pan, motor mounts, etc. But you prob were going to buy new ones anyway, right. The cost difference is minimal. I suggest reading MM&FF March 2002 issue. Article is called "Stroker Ace" on page 104. It can explain much better than I can. Good luck. Make a wise decision so you only spend your $ once! __________________ blue coupe:347 tfs, tremec

03-05-2004, 09:51 PM	#3
stvneil Registered Member Join Date: Feb 2004 Location: baton rouge, la. Posts: 18	i have been looking at longblocks (new) from $5500 to complete drop in's, balanced, blue printed dyno tested and broken in for $7500.00. would like to buy used for less. will be used for 80% street and 20% strip, any help would be appreciated. thanks neil

03-06-2004, 06:04 PM	#8
420nitro Registered Member Join Date: Nov 2003 Location: Rockford Posts: 596	You know what, it all comes down to what you really want. Do you want stealth, then go with a 302 based motor. If stealth is not that major of a concern then go with a 351 based motor. Don't get me wrong, you can if the funds are available, can even hide the 351 based motor under a stock hood. But all and all if it is between a 347 or a 408 I would go with a 408, hands down and never look back....And as a matter of fact that is what I did and have no regrets. Now if you would have said a 331 then were talking about a different story. I believe a 331 is better than a 347. Better rod ratio and able to spin the motor faster easier. You really need to answer alot more personal questions like the ones mentioned earlier and like what if any power adders. If you plan on running power adders then a 302 based motor is not something I would recommend with out up grading the block. A 351 based motor can handle more power and include power adders for the same amount of money. Yes, you will most likley need a new hood,oil pan,headers and stuff but wont you want to replace them anyway??? If you already spent the money on those parts then stay a 302 base motor. If not then I would be looking at a 351 based motor. Good luck with your project. As goes for soon to be turbo maybe he just didn't explain it correctley. I understood what STBT meant and it wasn't all that off. Everyone on this forum writes a little different, so I can understand where he might have been coming from. A lot of times people seem to come off way off base but after a while you get what they were saying. Just ask questions on what they meant before blasting people, would be my advise My 2 cents and dont give a shyte what others think

03-06-2004, 06:18 PM	#9
soon2Bturbo Registered Member Join Date: Jan 2004 Location: N. Illinois Posts: 15	Hey Jonnyboy, I don't like to insult people 'cause I think this forum is very helpful and useful. However, you run low 13's with a 331...ARE YOU KIDDING ME? Are you still using stock E7's. I don't care if you are at 2400 feet. You should be low,low 12's at worst. Maybe you're doing something wrong? And you can't blame traction because your MPH is way off too. 8 years ago I ran a stock bottom end, ported E7's, stock intake, w/ a b-cam on radials and went 13.3 @ 104. And you have a 331? Now you tell me what's wrong with this picture? Sorry dude, I don't mean to make you feel like shiznit, but, YEAH I DO!!! __________________ blue coupe:347 tfs, tremec

03-06-2004, 06:25 PM	#10
jonnyk Being stroked is great Join Date: Oct 1998 Location: Alberta, Canada Posts: 772	Say what you like. I have no illusions. At my density altitude on that day (4200 foot air), my ET corrects to 12.65 @ 111 mph. I don't blame traction, I run 17" street tires at the track, and won't be putting slicks on anytime soon. I'm also running 8.4:1 compression with a small cam, with 1 3/4" longtubes. Very bad N/A combo. Very good blower combo. I am looking to go above 125 mph in the 1/4 this year at altitude, which isn't easy no matter what size your engine is. Considering a brand new 405 horse ZO6 went 13.27 @ 107 mph on the same day I was at the track, I don't feel my times are all that bad. I just wish I had the chance to line him up once Also, a Procharged 2001 GT went 13.48 @ 110 mph the same day I was there. He had the extra oomph from that intercooler, but it didn't matter much on the launch pad If you think 2400 feet doesn't make a difference, you obviously haven't tried it, let alone on a day with lousy air. __________________ Novi 2000 now spinning off the snout of the 331... Mods Pics

03-06-2004, 07:51 PM	#11
stvneil Registered Member Join Date: Feb 2004 Location: baton rouge, la. Posts: 18	thanks for all the replies. the 408 blocks ran $5500-$7500.00. since then i have considered a 331 for $3500.00. i would replace the oil pan and headers since i would want a 2 1/2-3" exhaust system. power adders, i don't know, but i hate to spend money twice. i haven't worked on car engines in 30 years and i am just gettin back in to this. i have been running a stv boat with a 325 h.p. mercury engine. it is a 11 sec. 1/4 mile boat. i will be selling it soon and setting up this car to play with. i really don't know what i am doing so any help is appreciated. i do not want to spend a fortune on it, but i want something to hall ***. thanks again neil

03-06-2004, 10:00 PM	#12
jonnyk Being stroked is great Join Date: Oct 1998 Location: Alberta, Canada Posts: 772	Induction, heads, and the cam are everything. You can easily make a 331 run in the 11's all motor and have it very streetable as well. __________________ Novi 2000 now spinning off the snout of the 331... Mods Pics

03-08-2004, 12:32 AM	#13
soon2Bturbo Registered Member Join Date: Jan 2004 Location: N. Illinois Posts: 15	My apologies to jonnyk. I didn't know your combo was for forced induction. If I misinformed someone, then please correct me. However, there is a nice way to do it. I only get cocky when someone else gets cocky with me first. Anyway,too bad you couldn't have lined up with those guys, it would've been some good racin'. To stvneil...If the 331 is more within your budget, then go with it. Either one will give you the power you're looking for. Especially if it's been a long time since you've had a fast car. I know 'cause I returned to the racing sceen after being out for 6 years. I thought my friends '03 cobra was the fastest car ever. Until I realized I just wasn't used to speed. Now it doesn't seem as fast as it used to. Good luck. __________________ blue coupe:347 tfs, tremec

03-14-2004, 08:00 PM	#15
fiveOguy20 Registered Member Join Date: Sep 2002 Posts: 156	i agree its all in ur combo.. a 331 or 347 will run no faster than 302 if not part matched correctly. i've seen 347s run 14's soo lol. with my old 347 combo i only gotta best of 12.5 at 110. but that was with Bcam an Y303 heads. i added X cam an plan on vic. jr. heads this year, so should improve.