Cam and Vortec Head swap

[spanky1205]

To be honest I picked vortec heads because many people say they are a great upgrade from older castings, plus I can get the brackets and upgrade to a serpentine belt system with a new style A/C compressor relatively easy. I really do not have my heart set on any specific head or cam combo. The only thing I really want to use is my existing bottom end, which is a stock 350 with flat top 4 relief pistons and my quadrajet carb. I have been looking toward stock type heads because I am not out to make a fire breathing monster, I just want a good running truck that is reliable and gets decent fuel mileage. Power wise, to be honest I was perfectly happy with the original TBI engine that it came with, I was just not happy with all the knocking and mouse eaten wires. I have considered putting the TBI heads back on, but it seems like I could spend my money better elsewhere and get better results.

 

[4WDKC]

Same thing happened to me. One tiny hairline crack between valve seats, visible only after magnafluxing. The machinist said the head would probably be OK, but he'd hate to see me put $300 in the pair and have the crack get worse.

Fortunately I paid only $150 for the 1997 short block and heads, and was able to use the block, crank, and oil pan to build an engine for my 82 C10. Also ended up selling the heads for $125 to a guy who was fixing up a truck to sell that had overheated enough to crack both heads badly. Apparently that's a common problem --- overheat your Vortecs and they are toast. Don't you just love lightweight castings designed to save a few pounds per vehicle?

I bought another head from a yeard for $25 with a return policy incase it was cracked.

 

[Jrgunn5150]

To be honest I picked vortec heads because many people say they are a great upgrade from older castings, plus I can get the brackets and upgrade to a serpentine belt system with a new style A/C compressor relatively easy. I really do not have my heart set on any specific head or cam combo. The only thing I really want to use is my existing bottom end, which is a stock 350 with flat top 4 relief pistons and my quadrajet carb. I have been looking toward stock type heads because I am not out to make a fire breathing monster, I just want a good running truck that is reliable and gets decent fuel mileage. Power wise, to be honest I was perfectly happy with the original TBI engine that it came with, I was just not happy with all the knocking and mouse eaten wires. I have considered putting the TBI heads back on, but it seems like I could spend my money better elsewhere and get better results.

All depends on budget and intention. Personally, I look for thing's that have been crashed, assume they ran right up to the moment of impact, and use the parts without a trip to the machine shop.

Doing it the way I would do it, I would just throw Vortec heads on as is, no machining, no new springs, and deal with the .450 cam limit.

The one hang up is the specific intake you need you Vortec heads. If you are paying 150-200 for the heads, and 150 or so for the intake, then the cost is a wash and it's a good deal.

If you are paying 300 for heads then taking them off to have 300 more in machine shop work done, then they become not such a deal lol.

I personally use junkyard parts as is all the time, and it never really bites me. My truck is also a play toy and comes out on the weekends, so it's alot less critical.

 

[MikeB]

No way would I put used Vortec heads on an engine w/o having them magnafluxed and checking the deck surface for straightness. Otherwise you'll be out the cost of head gaskets and intake manifold gaskets, not to mention having to drain the coolant and take everything apart and reassemble again.

However, Jrgunn5150 makes a good point about heads that came off an engine that was running well. More than likely, they would be OK, or at least won't have any cracks that will causes leaks. Can't say the same for all engines in junkyard trucks, because engine probelms may have been the reason the truck was junked.

 

[Honky Kong jr]

No way would I put used Vortec heads on an engine w/o having them magnafluxed and checking the deck surface for straightness. Otherwise you'll be out the cost of head gaskets and intake manifold gaskets, not to mention having to drain the coolant and take everything apart and reassemble again.

However, Jrgunn5150 makes a good point about heads that came off an engine that was running well. More than likely, they would be OK, or at least won't have any cracks that will causes leaks. Can't say the same for all engines in junkyard trucks, because engine probelsm may have been the reason the truck was junked.

I'd have them checked regardless, whether running or not they are way thin in the deck area and it don't take much to warp or crack them.

 

[Jrgunn5150]

Yeah, I like to live dangerously lol. To me it's not such a big deal to swap out another head if I had too.

 

[spanky1205]

Thanks for all of the help gentlemen, I appreciate it. I have been looking up the different head and cam options everyone mentioned as well as trying to learn more about what and how to measure once I start taking things apart. I still do not fully understand what octane fuel I will need to use with a given list of parts.

Is there a way I can make some worst case scenario assumptions about my current engine and at least get a ball park idea of what type of fuel I will need?

I do not want to buy a bunch of parts and do the work to put them together just to find out I will need race gas to drive my truck. I found a compression ratio calculator and modeled a stock vortec engine but I can not even come close to that given my flat top pistons so I am thinking most 64cc chamber heads are going to be too small since I would prefer to run 87 octane.

Something else I have been trying to figure out that maybe easier to answer is, are all accessory bolt holes on SBC 350 heads the same? Meaning if I used a set of 882 heads, for instance, could I bolt on the serpentine belt system from a 1998 5.7 pickup?

Thanks again for you help,

 

[Honky Kong jr]

I do believe Vortec heads on an older block that had 76cc chambers yields roughly 10:1 compression with semi conservative timing you can run pump gas. I ran that combo in an S10 and ran it on 92octane pump gas with semi aggressive timing and it was fine.

 

[MikeB]

So you're sure the pistons are flat tops? 4 valves reliefs or 2?

Also, how far "down the hole" are they at TDC? Nominal is .025", but I've seen them at .030". But if the block has been decked they could be at .010" or less. That vs. .025" will bump the compression.

 

[Jrgunn5150]

Something else I have been trying to figure out that maybe easier to answer is, are all accessory bolt holes on SBC 350 heads the same? Meaning if I used a set of 882 heads, for instance, could I bolt on the serpentine belt system from a 1998 5.7 pickup?

Thanks again for you help,

My 882 heads have the same bolt holes as newer heads. The 60s and early 70s are missing some.

Vortec heads on flat top pistons and 87 is unlikely, I generally recommend getting an entire 5.7 and plopping a car bed intake on it

 

[Honky Kong jr]

My 882 heads have the same bolt holes as newer heads. The 60s and early 70s are missing some.

Vortec heads on flat top pistons and 87 is unlikely, I generally recommend getting an entire 5.7 and plopping a car bed intake on it

That's no fun.....more compression is better higher octane is better anyway.

 

[spanky1205]

So you're sure the pistons are flat tops? 4 valves reliefs or 2?

Also, how far "down the hole" are they at TDC? Nominal is .025", but I've seen them at .030". But if the block has been decked they could be at .010" or less. That vs. .025" will bump the compression.

Yep I am sure, I bought a cheap little endoscope off of eBay and stuck it down on of the plug holes. They are flat top piston with 4 valve reliefs. I was not able to scope all 8 cylinders, I am hoping I can do the rest and read a few numbers off the top of the piston so I can find more information out about them before tearing into the motor.

 

[Jrgunn5150]

That's no fun.....more compression is better higher octane is better anyway.

I don't disagree, I'm just going by his parameter's lol. If I were daily driving something, I'd want to put the cheap stuff in also.

 

[spanky1205]

That's no fun.....more compression is better higher octane is better anyway.

I don't disagree, I'm just going by his parameter's lol. If I were daily driving something, I'd want to put the cheap stuff in also.

If it was completely up to me I would do a 383, I have wanted to build one ever since I realized I could actually do it. Since my son wants this truck as his first vehicle, I have to keep that in mind as I add parts. There is no way a teenager working part time is always going to put premium in the tank when 87 is right there and $0.60 cheaper per gallon. After reading everyone's input and spending way more time looking up parts then I probably need to, I am leaning toward finding a set of 882 heads that will bolt on with the parts I currently have. That should give me a good running truck for a few $$ which will leave more money for fixing some of the other problems. I grew up in the north and currently live in the south, A/C sure would make driving this truck much more fun, even if it does not have all the power in the world. As always thank you gentlemen for the help, it is appreciated.

 

[4WDKC]

Without knowing how far in the cyl. the piston is the only safe bet is the 76cc head. Check with the machine shop and on craigslist you might be able to find a good used set for descent money.