I did a search for what I am wanting to do and found many helpful topics, and allot of not so helpful topics. Most of the topics were old though, so I am hoping that more recent input would help me better.

Here is my idea for my engine mods and I am about to start buying the parts next month:

LT4 Hotcam Kit (Thunder Racing)
HSR Vortec (Thunder Racing)
Vortec Heads
58mm TB (Thunder Racing)
Injectors (not sure what size)
Megasquirt II ECM

All this on the stoick bottom end until it blows, then I will Forge everything.

Now I am reading where the hotcam kit is good, but confused on what heads to get. I want Vortec, but not sure which ones to buy.

Moet Important Question: If I get the vortec heads, I was planning on getting them ported and worked. Is it worth getting them worked and all, or just go with Alum heads already worked (Which means I would have to go with the normal HSR)?

Question: What size injectors should I go to?

Question: Is the another combo that you guys have used, that would have the same results (or better) for the same price as this?

I am pretty set on doing these mods (using the vortec heads and VHSR), so I am hoping I will get good news from you guys about this combo.

 

bigger cam, like the XR276HR-12 would be real nice

vortec heads are a cool choice

throttle body is uneccesary

get new injectors, 24lbs would be good imo.

dont know anything about that ecm. sorry

 

So just use my stock TB?

I thought the LT4 Hot cam was the way to go for L98.....lol

 

its a great cam, but their is bigger thats still very streetable, of coarse this is all imo.

 

That depends on how "worked" you want to take them. Iron heads are much harder to work on and the time adds up. Paying a porter to do a complete port-job wouldn't be cost effective compared to an aftermarket aluminum head out of the box.
On the other hand you can have your porter do just minimal work to the valves and seats/throats only and get the most improvement for your money. The total money would still approach what you'd spend on better heads.

 

I would just go aftermarket and gasketmatch them all.

 

I went to a performance shop today. The guy works for the local pontiac dealer and as a side business he builds race cars. We talked and he showed me flow charts he had of the vortec and other heads. Straight out of the box the vortec heads out flowed another head witht he three angle valve job. He was telling me to get the heads bare and he would have his head guys port it to the 1209 gasket and put bigger valves in it (2.02-1.60). He will ask him tomorrow if he thinks they should do more porting than that, like 3 angle or w/e, but he felt that most likely that would not be needed. That the heads flow so good as they are, and gasket matching them and putting th bigger valves in, would be very *** as it is. Also he said the LT4 cam kit would be very good to do as well. He said he thinks everything I have picked out will match well and will give me allot of power. So I am going to go witht hat and when I am done I will dyno it and see what the results are. I am doing this a little at a time and for sure will have everything installed by this time 2006. Most likely it will be done by the end of summer. he told me not to get it painted till the engine work is done, so I will not be painting it next month. No biggie, cause i will still get the RA1 hood in Jan and have it set up to work.

Thanks for all the input, but I think I am straight now. Hope it turns out as good as we think it will......lol

 

Do not open the vortecs intake ports up to a 1209. the 1209 is a race head gasket. it is not for a vortec head.

vortecs are all about TORQUE...(small hi velocity ports.)
The intake port opening on a vortec head is big enough.
Match it to a felpro 1255 vortec intake gasket. This is as big as it needs to be. Little or no grinding is required. Vortec heads and vortec intake manifolds have a tapered
(trapizoid shaped)
intake port face opening. Do not remove this tapered trapizoid port opening on a street motor.

Only minor cleanup and contouring of the ports are required. If you want a large port race head go buy one. Do not try to make a vortec head into a large port race head. Same on the exhaust side. just clean up the walls and contour the guide boss. Smooth and blend the valvebowl below the seat.
Bigger is not better on these heads.

You will not see any gain in going to a 2.02 over the stock 1.94 without modifying the chamber (deshrouding) for the larger valve. In fact without specific porting and chamber deshrouding the flow will decrease.
(the edge of the larger valve is closer to the chamber wall at low/mid lift)



Stick with the stock 1.94x1.50" valves. Do a minor cleanup and smoothing on the ports, bowls and contour the guide boss in the valve bowl, that is all that is required.
Do not grind on the floor of the port just clean up the rough surface and smooth the port walls.
These heads are well engineered. Don;t F*&^% em up.
or you won;t have "Vortec heads" performance when you're done.

 

Thanks allot Fbird for the input. I noticed today when I was looking at the GM Performance engines, that they had stock vortec heads on engines registering 425 hp. I got to thinking then, that maybe they are good as they are. That would save me even more money (less porting). I did not know that the 1209 was for racing either, I just noticed people were porting theres to the 1209. I will go with the 1255 like you said.

Thank you allot for the input!

 

Any particular reason you don't want to use your 730 ECM and tune it for the new package?
Should work fine for what you're doing and would save you the cost and time of rewiring. Lots of stuff coming out for it like WB support and extended tables (see DIY PROM board)
IMO the 24 lb injectors may not be enough for the combo in the end unless you run higher fuel pressure.
30# seem to be in the HP range you are shooting for. Wouldn't want to lean out on the top end after all the work. Make sure your pump is up to the task in any event.
Many guys still say that a 52 mm TB helps a little and is kinda worth the cost but 58 is not needed for a 350.

 

I am not familiar with the 730 ECM, I will look it up and read about it. I have read up on the Megasquirt, and I was going to buy it already put together. All I have to do at that pooint is plug it into the factory wiring harness and then I can hook my laptop to it with the software....and upgrade as I go. The kit is less than $500, but I will read up on the 730 ECM and compare the two. As for TB and fuel pump. I did not put it on there but I was going to go to bigger fuel pump and bigger injectors. Was thinking of the SVO 30#, but was not sure if that was over kill or not. And I was going to read more about the TB to see which I need, but thus far I have been told same as you just said....to go with the 52 cause 58 is not needed. But I want to know if it will hurt or not, cause I have found a 58 mm BBK for sale (used) for $200. So will a 58mm hurt me, or is it just not needed for the money I would spend? I guess that is the question I need answered.

 

The 58 will just make you tune for the quick throttle openings a little more because the air flow will increase at a rate greater than the stock one so more tip in type issues will be there but nothing that can't be handled. The 52 from what I've heard is a bit easier on that issue. If the 58 is only $200 and you are buying one anyway then you might as well get it.
My setup is still in pieces or I'd have more definitive answers for you on that. I'm going HSR w/ 52 and 30# but is not the Vortec setup.
For the 730, you would need to get the chip adapter from Moates and then the Autoprom/flash and burn or his Ostrich but is easily do-able (is that word?) for real time tuning/logging. Lots of 3rd party logging applications are also availble for that application. I'm not real up on the technical capabilities of MS but weigh the options, might be able to save some $ and have everything you want.

 

Haven't you heard about the new Bowtie Vortec Heads? They out flow the regular Vortecs by 30hp out the box.

 

Yes I read about them, but haven't found any prices on them yet.

 

Around $800

 

have a link or some info on where I can buy them from?