Any Vortec knowledgables?

[sled_dog]

I have the 383 for my S10 sitting in the garage. It needs a tear down and hone to eliminate some rust from sitting. Anyway, the heads are nice and for a budget build they were THE choice for me. But I am sitting at 10.5+:1 right now. And I am considering throwing the engine in my C2500 pickup. If I do that, the compression is just too much. So I'm looking at what head options I have.

So who makes heads that accept the Vortec intake and have a 72 or 76cc chamber volume? Only option I have found is AFR's 180cc street heads. In the end I think they are the best option anyway. If I am spending $1000 on heads, why not spend $1400 and just get the best right off the bat?

The other thing is, what are the limits of the Vortec fuel system? I know the pintle injectors are only 19lb-hr, so thats not much fuel to feed a 383 with an LT4 Hot Cam and AFR heads. Think the intake/fuel system could handle that kind of power? I've heard it said before that a 383 with LT4 Hot Cam is basically the limit of what the system can handle. Thoughts?

Don't know if there are any Vortec knowledgables here, just wondering if someone knows more on the system.

 

[daleearnhardt01]

Find yourself one of those GM Marine application intakes for the Vortec... Its a MPFI setup and then you can do whatever you want.....

 

[beater_k20]

or a Vortec TPI base, and convert it to TPI

or, if you wanna get really fancy, you could go with a Ram Jet, they're not really as expensive as one would think.

 

[dyeager535]

I know they make thick head gaskets to drop the compression a bit, in this situation it might work for you.

The cam is another variable in compression ratio tolerance...10:1 is fairly high for 87 octane, but it CAN be done. Dunno if thick gaskets could shave off enough to get you to 10:1 or a bit less and be practical, but would be cheaper than other alternatives I'd imagine.

19lb/hr injectors seem small even for a 350, I'd look to at least the 6L engines to see what they ran in those. You'd just have to look at the system as it runs to see if it's constantly trying to richen the system though. As I recall there are formula's to calculate the injector sizing, but I also know the Vortec injection setup isn't a "standard" injector either, if it matters.

pro-topline/RHS sells Vortec head replacements, no idea if anyone makes ones with LARGER chambers though.

 

[sled_dog]

getting a gasket to lowere my compression to where I want it to be would be absurd. They'd have to be like solid steel spacers, haha.

I don't want to convert to TPI because the truck has a 4l80e. I'd have to buy a standalone TCM for that, or go full manual. And if I convert the 4l80E to full manual, I will just go propane on the engine and forget fuel injection.

And if I could find one of the marine intakes, I would do that swap in a HEARTBEAT! If you look, there is a post by me somewhere sending a call out for one. I really want one, but damned if I can find one. Its a pretty hard to find item.

Yeah and I just found one guy with a wait list to sell Marine intakes.... $750!!! http://www.pacificp.com/forum/viewtopic.php?t=1361&highlight=

 

[JEBSR]

getting a gasket to lowere my compression to where I want it to be would be absurd. They'd have to be like solid steel spacers, haha.

May sound absurd but engine builders have been using thicker and thinner gaskets to change compression ratio's for longer than I have been around. Never seen one fail do to the thickness. If it wasn't safe they wouldn't sell them. However with that said I don't know if it will get you as far down as you want to be.

I run 24 lb injectors almost everytime I have built a 383 with TPI and it seems to be a good injector size for that setup.

 

[beater_k20]

I know they make thick head gaskets to drop the compression a bit, in this situation it might work for you.

wont exactly work right with a head with a chamber such as the Vortec. the Vortec chamber (and those similar to it) rely on a certain quench distance and combustion chamber shape to promote a better burn. open the quench distance too much, and you create hot spots in the chamber which lead to preignition (pinging)

 

[dyeager535]

How about cleaning the combustion chambers up? What kind of CC gain do you typically see from that?

Vortecs are pretty clean castings, but it wouldn't be bad to do in any case.

 

[sled_dog]

minimal cc increase from cleaning a chamber. You'd have to reshape the chamber to really make a gain. thus defeating one of the good points of a Vortec head.

 

[neverendingproject]

I think world castings makes some that have a bigger combustion chamber.

 

[beater_k20]

honestly, if you're considering throwing enough money at it to replace the heads, why not just swap pistons? it'll be way cheaper. and its going to be apart anyways.

 

[1979jimmy350]

I don't want to convert to TPI because the truck has a 4l80e. I'd have to buy a standalone TCM for that, or go full manual. And if I convert the 4l80E to full manual, I will just go propane on the engine and forget fuel injection.

this is not true, you can run TPI and the 4L80E on the smae computer, using TPI would actually let you run some cool things like DIS ignition, you could do sequential TPI unlike the stock batch fire system look on thirdgen there is a lot on OBD II TPI engines im actully working on running TPI with a 4L60E using a 94 TBI PCM to controal it all

 

[sled_dog]

true but new pistons would do nothing to increase power, and I will have to get the engine rebalanced. As is it is, the more I think, I am just going to do little bolt on crap and a tune on the Vortec engine. it runs, it uses 1/2 a qt of oil per 3,000 miles(which is likely the seeping oil cooler lines) and its still strong. I'm gonna pull the 383 apart, hone it, leave the heads off and just put it on the back shelf in the garage. A project for a later time.

 

[beater_k20]

then why waste time honing it? just oil it up good.

 

[sled_dog]

already rusty, rather not have the rust that is there get any worse. maybe I won't bother for now. Its sitting oiled up right now and hasn't really gotten any worse. but the shop it is in now is a little more climate controlled than our garage is at the moment. Everything Dad has done to our garage, he hasn't bothered to install the heater yet...