onesmartidiot

My car blew up in 2009 due to the cat-clogging up. Actually I have no idea if it is blown up or not, I cut off the exhaust infront of the cat and can get it to idle.... kinda..

I've been back and fourth on if I should save the 70k mile engine and keep it matching or not. There is a "hate me" build some magazine did, but involves alot of knowhow and machine work. Not sure how well I could undertake it.

I'm sad that my car has been towed around and banged up the last few years since it no longer runs, I think I'm going to just pull the trigger, save my old block for a rainy day, and put a 350 in there.

I am finding this ( http://www.jegs.com/i/GM+Performance...FaFDMgodnWcArg ) appealing for the price. I dont want to buy anything off craigslist so this seems like the next best bet.

I would like to put vortec heads and intake on it with a edlebrock 650 carb. I figure that will be enough juice to get my sunday driver back.

What are your thoughts on this setup? I was also reading up on cams which further confused me, but it seems like this is a solid way to go for making 300 horsies or so pretty easily.

-b

midias

If all you want is 300hp you can probably just swap the cam and be done.

naf

iTrader: (7)

Look at either the L31 longblock or the HO. Both come with the vortec heads and each has the one piece rear seal.

The HO will have a slightly better camshaft although it's a flat tappet. I'd verify that it is machined for a roller cam cause you may want to go there one day. The L31 should have the roller cam, lifters, etc.

The L31 will likely be less expensive than your original choice once you factor in the heads and gaskets. You'll also get a roller motor and better compression.

All you'll have to add is a flexplate, intake and carb to either along with maybe a cam of your choice.

five7kid

iTrader: (14)

My thoughts?

I wouldn't do it. That engine is for appliance repair fleet vans abused by non-owner drivers. That 260 HP is gross flywheel HP, not the "net" HP your 305 is rated at (in other words, not much more than the 155 HP your 305 was rated at). The compression is low, the heads terrible (why buy something you aren't going to use?), flat tappet cam, 2-piece rear main seal (read: leaker), castings most likely not of US origin - I wouldn't bother.

Where were you planning on getting the Vortec heads? You do know you need a different intake manifold, right?

It makes a lot more sense to me to start off with an engine that already has Vortec heads: http://www.jegs.com/i/Chevrolet-Perf...30283/10002/-1

Also has 1-piece rear main seal (yes, you'll need a new flexplate - $50, if you don't shop around), higher quality pistons, roller lifters (big improvement over flat tappet), better compression (even with Vortec heads on the Goodwrench engine), and better quality castings. Only thing I'm not sure about is whether it will have the mechanical fuel pump provision (drilled/machined, cam lobe). Even if it doesn't, I'd still use it and do what it takes to hook up an electric fuel pump over that Goodwrench engine.

Also have zero love for Edelbrock carbs. The stock computer q-jet is the best street/performance carb available, factory or aftermarket. Keeping it, even if you have to buy a rebuilt, will be cheaper in the long run than putting on a new piece of crap.

Of course, none of this really addresses your original statement - whether a clogged cat is the cause of all your issues.

BTW, I had one of those Goodwrench engines in a full-size '84 conversion van that originally had a 305. While we put a lot of miles on it, including pulling a horse trailer weekly and occasional long trips, it was really lame, power-wise.

onesmartidiot

Thanks for the info, I noticed the L31 truck block awhile ago but did not know how well it would convert over into the camaro. I mean... a 350 is a 350 right?

What would be a reasonable expectation of the power this L31 could produce with a better cam? I have swapped engines before but have never cracked one open, so lift and duration are magical words to me which I do not understand.

I am partial to edelbrock because the performer carb did miracles on my 454 in my Winnebago. The quadrajet left me stranded in Florida on vacation. I flew back down with the edelbrock 750 and the old girl sang the whole way back to Ohio (while getting an extra 1.3mpg!)

Anyway, I would need to convert the the camaro to an electrical fuel pump for this L31 to work, what am I looking at there?

Also I would imagine that while low miles, my 700r4 would need beefed up as well?

five7kid

iTrader: (14)

Cams - "Lift" means how much the cam opens the valve. It is usually stated "at the valve", because the rocker arm multiplies the actual lift of the cam lobe (1.5:1 is the stock SBC ratio). The engine I linked has a cam that opens the intake valves 0.414", and the exhaust valves 0.428", both with 1.5:1 ratio rocker arms. In general, the more the valves are opened, the more fuel/air can flow into the cylinder, meaning more power.

"Duration" means how long, in crankshaft rotation degrees, the valve is open. In general, the more duration there is, the higher the RPMs the engine will make power, and the more power it will make - at the expense of low-RPM driveability, and fuel economy. The "@ .050"" part means the duration is calculated starting when the valve has opened .050" and until it is .050" from completely closing. Without getting into too much detail, that is the "practical" point at which the valve will start flowing, and is a more accurate picture of how the cam will act than simply stating duration from the point the cam lobe starts to lift to the point when it no longer has lift.

So, you can get a cam with more lift and duration to get more power, but that has an effect on the valve springs. Vortec valve springs are notoriously weak, and can't handle much more than stock lift or duration. So, if you want to put a different cam in, be prepared to replace valve springs as well. And, at that point, with Vortec heads, that's where things start to get complicated.

With the cam that comes in it, the L31-R engine will probably make a good 250 HP with good exhaust (factory 305 exhaust is horrible - plan on replacing every piece of it with aftermarket stuff). That's an apples-to-apples comparison to the 155 HP your 305 is probably rated at.

A stock TH700R-4 won't be at risk at that power level. Of course, it wouldn't hurt to do the "normal" TH700 upgrades, but you shouldn't have to expect to spend $2k on a fully built TH700.