Help with parts for a high revving 358 Build.
Thread Starter
Registered User
Joined: Jun 2006
Posts: 919
From: New Brunswick,Canada
Help with parts for a high revving 358 Build.
Here's what I'm thinking. My engine builder says i can do this safely:
.40 over block
Stock Crank
Stock Rods
The lightest forged pistons I can get(11:1 compression)
All ARP bolts
Everything machined and perfectly Ballanced, right down to the spec flywheel.
I'm going to use my heads which are VERY close to LE2's, a GM 847 or mabey a custom grind and valve spring to match the cam. Electric water pump and double roller chain. Plus everything in my sig.
I want it "LIGHT" and to spin it to about 7k, but just street use.
WHY you ask? I dont have the money for a new crank and rods and I feel I can make all the power I want(450 RWHP) with this combo.
What do you think? Or what would you do different...
Thanks
.40 over block
Stock Crank
Stock Rods
The lightest forged pistons I can get(11:1 compression)
All ARP bolts
Everything machined and perfectly Ballanced, right down to the spec flywheel.
I'm going to use my heads which are VERY close to LE2's, a GM 847 or mabey a custom grind and valve spring to match the cam. Electric water pump and double roller chain. Plus everything in my sig.
I want it "LIGHT" and to spin it to about 7k, but just street use.
WHY you ask? I dont have the money for a new crank and rods and I feel I can make all the power I want(450 RWHP) with this combo.
What do you think? Or what would you do different...
Thanks
Registered User
Joined: Oct 2001
Posts: 2,684
It will work because a lot of people have done it before, but the weaknesses will be 2 bolt main caps and stock crank flopping around if it gets revved too high, make sure your new rod bolts are installed prior to resizing, then build the valve train good so it won't float, and make sure you buy a good oil pump with a solid coupler and get rid of that plastic one.
Registered User
Joined: May 2006
Posts: 1,855
From: Ohio
It will work because a lot of people have done it before, but the weaknesses will be 2 bolt main caps and stock crank flopping around if it gets revved too high, make sure your new rod bolts are installed prior to resizing, then build the valve train good so it won't float, and make sure you buy a good oil pump with a solid coupler and get rid of that plastic one.
Thread Starter
Registered User
Joined: Jun 2006
Posts: 919
From: New Brunswick,Canada
It will work because a lot of people have done it before, but the weaknesses will be 2 bolt main caps and stock crank flopping around if it gets revved too high, make sure your new rod bolts are installed prior to resizing, then build the valve train good so it won't float, and make sure you buy a good oil pump with a solid coupler and get rid of that plastic one.
Thanks.
Registered User
Joined: May 2006
Posts: 1,855
From: Ohio
Registered User
Joined: Dec 2004
Posts: 968
From: Wichita, KS
My motor is exactly what you're describing. I shift it at 7K.
IMO, I wouldn't bother with your stock rods. It's not that they aren't a good rod, but by the time you buy good arp bolts in them and pay to have them re-sized, and have the small end bushed for full floating wrist pins, you'll have spent as much or more as a decent set of aftermarket rods. I went with a set of Scat I-beams, with 7/16 ARP cap screws rather than the standard 3/8 bolts. These certainly aren't the best rods out there by any means, but they are definately a little stronger than stock while being the same price or less than reconditioned stockers. Plus they are already bushed for full floating wrist pins, which most any decent forged piston will require.
As for the crank, I'm running a stock one, no probs. Just make sure everything is balanced perfectly.
If I were you, I'd spend alot of time carefully researching and selecting quality valvetrain parts if you wanna spin 7k reliably. GM847 will get the job done, but IMO you'd be better off with a custom grind and following the instructions of whoever specs your cam as far as what springs to use and what installed height they're to be set at. And be darn sure you get your pushrod length correct, or else you'll be causing alot of abnormal wear. Trust me on this, I've been through a few valvetrain parts that were suppose to be "quality stuff"
IMO, I wouldn't bother with your stock rods. It's not that they aren't a good rod, but by the time you buy good arp bolts in them and pay to have them re-sized, and have the small end bushed for full floating wrist pins, you'll have spent as much or more as a decent set of aftermarket rods. I went with a set of Scat I-beams, with 7/16 ARP cap screws rather than the standard 3/8 bolts. These certainly aren't the best rods out there by any means, but they are definately a little stronger than stock while being the same price or less than reconditioned stockers. Plus they are already bushed for full floating wrist pins, which most any decent forged piston will require.
As for the crank, I'm running a stock one, no probs. Just make sure everything is balanced perfectly.
If I were you, I'd spend alot of time carefully researching and selecting quality valvetrain parts if you wanna spin 7k reliably. GM847 will get the job done, but IMO you'd be better off with a custom grind and following the instructions of whoever specs your cam as far as what springs to use and what installed height they're to be set at. And be darn sure you get your pushrod length correct, or else you'll be causing alot of abnormal wear. Trust me on this, I've been through a few valvetrain parts that were suppose to be "quality stuff"
Last edited by Colin91Z; Apr 27, 2009 at 10:00 AM.
Registered User
Joined: Jul 2002
Posts: 1,942
From: Kissimmee, Fl, USA
.040 over can be a concern with some blocks due to core shift. Before boring you can have the cylinder wall thicknesses measured to be sure. I know guys have done it but it's better to be sure....
Thread Starter
Registered User
Joined: Jun 2006
Posts: 919
From: New Brunswick,Canada
Good point... i never considered that the .40 over pistons would be more money. I was just looking for the most cubs...
Thread Starter
Registered User
Joined: Jun 2006
Posts: 919
From: New Brunswick,Canada
My motor is exactly what you're describing. I shift it at 7K.
IMO, I wouldn't bother with your stock rods. It's not that they aren't a good rod, but by the time you buy good arp bolts in them and pay to have them re-sized, and have the small end bushed for full floating wrist pins, you'll have spent as much or more as a decent set of aftermarket rods. I went with a set of Scat I-beams, with 7/16 ARP cap screws rather than the standard 3/8 bolts. These certainly aren't the best rods out there by any means, but they are definately a little stronger than stock while being the same price or less than reconditioned stockers. Plus they are already bushed for full floating wrist pins, which most any decent forged piston will require.
As for the crank, I'm running a stock one, no probs. Just make sure everything is balanced perfectly.
If I were you, I'd spend alot of time carefully researching and selecting quality valvetrain parts if you wanna spin 7k reliably. GM847 will get the job done, but IMO you'd be better off with a custom grind and following the instructions of whoever specs your cam as far as what springs to use and what installed height they're to be set at. And be darn sure you get your pushrod length correct, or else you'll be causing alot of abnormal wear. Trust me on this, I've been through a few valvetrain parts that were suppose to be "quality stuff"
IMO, I wouldn't bother with your stock rods. It's not that they aren't a good rod, but by the time you buy good arp bolts in them and pay to have them re-sized, and have the small end bushed for full floating wrist pins, you'll have spent as much or more as a decent set of aftermarket rods. I went with a set of Scat I-beams, with 7/16 ARP cap screws rather than the standard 3/8 bolts. These certainly aren't the best rods out there by any means, but they are definately a little stronger than stock while being the same price or less than reconditioned stockers. Plus they are already bushed for full floating wrist pins, which most any decent forged piston will require.
As for the crank, I'm running a stock one, no probs. Just make sure everything is balanced perfectly.
If I were you, I'd spend alot of time carefully researching and selecting quality valvetrain parts if you wanna spin 7k reliably. GM847 will get the job done, but IMO you'd be better off with a custom grind and following the instructions of whoever specs your cam as far as what springs to use and what installed height they're to be set at. And be darn sure you get your pushrod length correct, or else you'll be causing alot of abnormal wear. Trust me on this, I've been through a few valvetrain parts that were suppose to be "quality stuff"
Thats ALL good advice.... Thanks. What did you use for Pistons? Valve train is where I'm going to make my power, so I'm going to take GREAT care in what i pick and how its set up.
Registered User
Joined: Dec 2004
Posts: 968
From: Wichita, KS
I used Probe pistons. They're a pretty nice piston for the money. However, if I built this particular combo again, I would have opted for Mahle Power Pack pistons. They're more expensive, but they're better quality, they're coated, & come with a nice set of rings. By the time I bought the Probes plus a nice set of Total Seal rings, I ended up spending more than the Mahles would have been
By the way, when you're selecting your pistons, don't be afraid to get your compression ratio in the mid-to-high 11s...it'll only help. LT1s love compression
I run 11.8:1 on pump gas with no detonation...and the pump gas here in Kansas is only 91 octane....
Last edited by Colin91Z; Apr 27, 2009 at 08:29 PM.