Pro's & Cons for a 370ci budget build
04-29-2013, 03:29 PM
#1
Pro's & Cons for a 370ci budget build Cam across a couple of 370ci builds got me thinking.
What are the pro's & cons of doing this? I would love to do a 408ci build but just not going to be able to do it just yet.
I have a LQ4 short block & stock 243 heads (not milled)
Currently looking at Tick's Polluter stage 3 for cam.
What are the pro's & cons of doing this? I would love to do a 408ci build but just not going to be able to do it just yet.
I have a LQ4 short block & stock 243 heads (not milled)
Currently looking at Tick's Polluter stage 3 for cam.
04-30-2013, 10:10 AM
#2
370 vs 346 - 370 has more bore and can make more power; has a stronger block, but it's heavier and can't take as much timing/compression due to the iron block
370 vs 408 - 370 is cheaper but 408 is stronger and makes more power with more stroke
If you're boosting an engine or running lots of nitrous, 370s end up being a good balance between strength and cost effectiveness. Also, I prefer to run a shorter stroke in boost or nitrous applications in order to use a stronger piston with a thicker ringland. The stock GM crank is good to 1k HP, so for most folks, a 370 is plenty.
All motor, 370s are good as well. 6L with the same heads/cam as a 346 usually make another 10-15HP and a good 20-30ft/lbs more.
370 vs 408 - 370 is cheaper but 408 is stronger and makes more power with more stroke
If you're boosting an engine or running lots of nitrous, 370s end up being a good balance between strength and cost effectiveness. Also, I prefer to run a shorter stroke in boost or nitrous applications in order to use a stronger piston with a thicker ringland. The stock GM crank is good to 1k HP, so for most folks, a 370 is plenty.
All motor, 370s are good as well. 6L with the same heads/cam as a 346 usually make another 10-15HP and a good 20-30ft/lbs more.
04-30-2013, 10:41 AM
#3
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I have never heard of timing and compression having a limit with an iron block verses an aluminum one. Care to eloborate?
Weight is the only con. Everything else, pro
Weight is the only con. Everything else, pro
04-30-2013, 12:03 PM
#4
Yeah, try to run as much timing in an iron block combo with similar compression to an all aluminum motor. You can't. I've never seen it. You always have to pull 3-5 degrees.
That's why must engine builders recommend slightly lower compression on the iron block builds given all other factors being the same (compression, dynamic compression, plugs used, etc.)
That's why must engine builders recommend slightly lower compression on the iron block builds given all other factors being the same (compression, dynamic compression, plugs used, etc.)
04-30-2013, 02:56 PM
#7
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Yeah, try to run as much timing in an iron block combo with similar compression to an all aluminum motor. You can't. I've never seen it. You always have to pull 3-5 degrees.
That's why must engine builders recommend slightly lower compression on the iron block builds given all other factors being the same (compression, dynamic compression, plugs used, etc.)
That's why must engine builders recommend slightly lower compression on the iron block builds given all other factors being the same (compression, dynamic compression, plugs used, etc.)
I've run LS2 and LQ block in same configuration on same tune with same compression and cam. No difference in my combos was seen. Same output.
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04-30-2013, 09:30 PM
#10
I have never heard of timing and compression having a limit with an iron block verses an aluminum one. Care to eloborate?
Heck, I would imagine that a stronger iron block would be able to take MORE compression and timing than a soft aluminum block with thin iron liners...
04-30-2013, 10:10 PM
#12
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So what, you think an aluminum block has aluminum sleeves in it to? That's why it can take more compression?! GTFOH! It has cast iron cylinder liners in it!
That is the funniest thing I have read yet.
OP, what are your goals for this motor? It you want budget, pick up a good set of used rods, some nice forged pistons and use the stock crank. Put a good cam/spring package in it and let it eat.
That is the funniest thing I have read yet.
OP, what are your goals for this motor? It you want budget, pick up a good set of used rods, some nice forged pistons and use the stock crank. Put a good cam/spring package in it and let it eat.
05-01-2013, 01:06 PM
#13
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Yeah, try to run as much timing in an iron block combo with similar compression to an all aluminum motor. You can't. I've never seen it. You always have to pull 3-5 degrees.
That's why must engine builders recommend slightly lower compression on the iron block builds given all other factors being the same (compression, dynamic compression, plugs used, etc.)
That's why must engine builders recommend slightly lower compression on the iron block builds given all other factors being the same (compression, dynamic compression, plugs used, etc.)
05-01-2013, 04:48 PM
#14
I made this thread before I talked it over with Martin @Tick. I told him what I was doing and my options. Stay as a 364 or do a 370. He made some good points that in doing a 370 build now and in a couple of yrs a 408, I'd just be saving on machine costs in the long run but adding more to my 408 build later on because I may or may not be able to recoup the pistons & rods for the 370 build when I decided to do a 408 build.
So I'm going to go with his Polluter stage 3 and BTR valves to go with the 243 heads and LQ4 short block that will have LS2 pistons I picked up. I still want it street drivable (such a variable term) but want to have some fun too.
Having a shop (Seems to have a good rep from the LS community here and is also a race shop, might mean I'm low priority since it's race season here)
(1) check the block (magnaflux) + hot tank it $60 + cost of cam bearings
(2) resize the rods for arp bolts $75-$80
(3) balance the crank and rods $225
(4) have them get it to a short block. $200 + crank/rod bearings
05-01-2013, 06:35 PM
#15
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Glad you are not touching the bore size....yet! Remember this isn't a gen 1 sbc or sbc so once you bore it .030" and hurt it you better hope that it doesn't eat a cylinder wall! By that time you better be looking for another block IMO. Now my gen1 sbc, hell .030" is the starting bore!
I am building a motor to go into the 4.8-.9x range on a stock block. All i did to my own block was go .005" over and called it good just because the block was perfect. No need in going to what some say is the max for these block right off the bat. Plus, these pistons were actually cheaper than going .030" over!!! Lol!
Good luck with it!
I am building a motor to go into the 4.8-.9x range on a stock block. All i did to my own block was go .005" over and called it good just because the block was perfect. No need in going to what some say is the max for these block right off the bat. Plus, these pistons were actually cheaper than going .030" over!!! Lol!
Good luck with it!
05-02-2013, 12:15 AM
#16
As Pred said, the combustion process happens outside of the block. So, that's why we didn't know. It wasn't heatsoak, but that was our guess being we're in the FL humidity.
Anyway it's based on experience. Not internet guru bullshit.
With that, I'll be the first to admit when I'm wrong, so maybe I'm remembering it wrong. But I've always stayed away from iron blocks because of that, rightly or wrongly.
