Revving and ARP Mains

[Jesus5150]

I'm currently in the process of building my 350 in my 69 Longhorn. I plan on leaving the bottom end stock this year and building the top end. Next year i'll 'pick up a 4 bolt block and do a forged 383 rotating assy so i'm not putting much cash into the bottom end.

I Currently have a 2 bolt block that looks like it may have flat tops already installed. I got it from my uncle when he upgraded to a 454 and said it ran great. He didn't build it so can't verify what the internals are. But they are .030 over and appear flat. ANYWAY

I bought a Lunati Voodoo 280/286 Solid Flat tappet cam that i'll be throwing in along with Lunati Beehive springs and lifters that they reccomend as well as a valve girdle for support.

Ill be adding a set of aluminum heads, a Victor Jr intake and maybe arp head bolts.

My 2 questions are:

can I rev higher now that the cam/lifters/springs have been upgraded, knowing the rods, crank and rod bolts are stock?

Must I line hone the block if i switch to ARP main bolts (not studs, They're only 30 bucks)?

[hamjet]

In short, I would also get ARP rod bolts, have them checked for roundness after torqueing them because of higher torque. same goes for mains. The only reason for line boring the mains is if they are not aligned, take it to a machine shop and have them check it with the ARP main bolts torqued, or if you have the mics and precission tools, do it your self. 2 bolt mains never bothered me as long as its kept under 6800 7000 RPM. (how many people do you know who threw the crank out the bottom because of 2 bolt mains) Plus, cast pistons aren't too safe at higher RPMs either.

[Jesus5150]

Here's a picture of the block and pistons. Not the best, but I found it in my computer and decided to post it.

[GRX]

can I rev higher now that the cam/lifters/springs have been upgraded, knowing the rods, crank and rod bolts are stock?

The new upper end may allow you to rev higher yet the same potentially worn bottom will be under even more stress. Regardless if you have ARP studs installed or not checking the mains is never a bad idea. And always have your rods checked. The most often over-looked components in my experience. I have never seen a set with significant amount of miles on them which weren't stretched to some degree. With today's prices best bet is to buy a set of steel rods ready to go.

[Blue Rat]

If you are installing ARP for the main studs. It does need to be line honed. The machine shop should let you know on that when they torque them down. Also install a ARP stud for the oil pump. An using ARP rod bolts are always a good choice.

[68post]

A set of cheap new rods should be as cheap as rebuilding your old stock rods, and may insure you have a good shortblock for a spare later.
I'd check the existing main bearings when you break it down, if they look fine - odds are you'll probably be ok and not need an align-hone if using bolts instead of studs. Studs generally require an align-hone.

Good parts and balance will let you rev the snot out of it.


4 bolt mains help to stop the main caps from movement and fretting. All the 350's I've broken down - the 4 bolt ones usually had their main bearings in better shape.
Higher engine stress from of a variety of factors are what cause the need for a stronger foundation.

[tjsblazer]

If I'm reading your initial post correctly, you are intending on building a new top end on to an old bottom end, and then transferring that newish top end in a years time to a new bottom end with a larger CI displacement. This is going to require a lot of planning on your part to ensure you are happy with the end product and you already have decided on a Cam.
The engine characteristics of a 350 with a given compression, heads, cam, induction is going to be different when you put those top end parts on an engine with 10% more CI and potentially different compression.
Displacement and Compression and Valve timing events must be matched to satisfy the intended application are desired performance characteristics or you are leaving stuff on the table and in the end most likely won't be happy with the end product.
I personally would do the whole long block now or if $ is the issue save until I could. I know for me it would be cheaper in the long run and I would be happier with the result.
If you have to do it in two parts as you outlined, you will have to build with your 383 specs in mind and chances are the 350 will be a bit of a dog down low in a heavy 69 longhorn built that way as the rpm powerband will be higher than desired.