Spending months with my 3rd gen getting it subpar, I figured why not consider stepping up to an LT1. Consider that an LT1 4th gen makes 275 hp stock. One can also be had used for around $4500-7000. So I figured why not propose a setup and see if it is really worth it. To me, an LT1 to LT4 conversion kit is very attractive, considering the 450+ hp it makes for only $2200.

Here is my proposed setup for my current stock LO5 engine:
Open Element $paid
Vortec Heads $600
LT1 Cam (Mild yes, but cheap and easy) $100
Intake (ZZ4?) $200
Throttle Body (Holley?) $200
Total $1100 (at least)
[plus, do I need to consider a bigger fuel pump, stall conv, and chassis strengthening or can I stay stock with those]

Now pair this with a complete exhaust (2055s, highflow cat, 3" catback) and it should be good for 330 hp correct. I have chip tuning so I didnt really figure in the major gains from that. Maximum I figure 350 hp, correct?

I am moving soon and will be doing 5 hours of highway driving every so often. I want performance but also reliability. Thus, paying a $150 per month car loan on a used 4th gen is kind of promising. I absolutely love 3rd gens but its somewhat harder to get a loan for rebuilding the topend of a motor.

So will these parts work togethor? If not, what intake/TB will work with the vortec heads w/o modification. Im looking for a simple bolt ons so suggestions are welcome. A fellow employee I work with is getting a new 05 mustang so either route I take I at least hope to show him up at the track/street (at least once I get some good 245/45/17 tires)

 

Don't mess around.

Sometime in Janaury, GM Part # 12578105 should be available. I'm sure fitment would be interesting though.

But to answer your question. The LT4 has some goods, on the other hand, you can get more than 450hp for the price. You could get a shafiroff crate motor with more than 450hp for the same price. you can get a turnkey motor for about 9k from them (http://www.shafiroff.com/434_595_engine.asp) its almost 600hp.

 

what is GM Part # 12578105? As far as spending the same price towards an engine swap its out of the question. I already swapped in the LO5. I want to keep the block and just decide on either rebuilding the topend or buying a new 4th gen. My engine only has 70000 miles on it. however 170000 are on the car vs. maybe only 90000 from a used 93+ camaro.

With those parts what kind of hp/tq numbers am I looking at? I consider 450 a great number and spending anything over $2000 on an engine is just not going to happen.

I would enjoy owning a 6speed too so that is also something motivating me

 

Your basically going to have an LT1 with a slightly older block. The vortecs are basically an iron gen 1 version of the lt1 head, same ports, same chambers. The intake will flow with the lt1 intake so everything should be very very close to what a stock LT-1 makes.

That cam is slightly smaller than what comes in the 330 HP gm crate motor, so I'm guessing with the headers and properly tuned your going to be making 300-320 hp. Chip tuning won't make hp but it will keep you from loosing it. You'll have plenty of time wraped up in getting it tuned right.

Sounds like to me that you have already made up your mind about a 4th gen. Most people build up 3rd gen's because it's fun and they are great platforms. If your only worried about bottom line performance I would go with the 4th gen.

 

Thats the part number for the LS7, when it becomes available.

 

So what is the cheapest vortec-compliant intake manifold and throttle body that will get me close to that 330hp mark? I enjoy working on my formula and getting 300+ horses for less than $2500 could possibly be worth it.

However, wont I need to invest in a new stall converter, fuel pump, bigger injectors, possibly other misc things to even run smoothly?

 

The intake and throttle body isn't whats limiting you, it's the cam. It's even on the small side for a stock 305. You need to look into something bigger. If I were you I would skip right to the hot cam. It should get you near 400 hp with the right bolt ons.

I would go with the performer rpm intake and find a TB off of a 454, it should have the 90 pph injectors which will make tuning much easier. If you get the holley TB it comes with smaller injectors that must be ran at higher pressure to get the advertised rating out of them.


As for the fuel system, you'll need a bigger pump, the 454 TB should have the bigger injectors, and you won't need the stall with the LT1 cam, but it wouldn't hurt. The hot cam will want at least a 2000 stall but would be happier with something in the 2400 range.

I will warn you the hot cam is pretty big to be tuning with no experience. I would get busy now learning the ropes so you'll be ready to tune with the new combo.

 

Performer RPM intake, I forgot if that worked with the vortec heads or not. I was thinking of grabbing an S10 stall to do the job.

The hotcam sounds good but can the vortec heads support the lift? LT1 was pretty much only chosen for its easy installation and no need to modify the vortecs. If not, then I can probably just solve the chip tuning problems of the LT4 and run with that. Id enjoy being in LS1 territory with a 380+ hp car.

 

I'm pretty sure they make an vortec rpm intake. The stock vortec heads won't support the hot cam's lift, but he machine work wasn't all that expensive when my brother had his done. If your not wanting to get into chip tuning I would look into the 4th gen, none of this will work well without tuning. The s10 stall is a great little converter for the money, thats what I'm running.

 

ya i think summit sells a version of the vortec heads already machined for bigger lift cams. Their around $750 for the pair. Not much extra at all considering the regular cast irons are $520. Thats the price fully assembled but as I caculate this even further there are many hidden costs. The heads come fully assembled i believe but ill still need new 1.6 rockers ($100) springs (i think-$60), new timing chain (?), ignition and more. MonteSS Did you experience any problems with your vortec, rpm intake, and 454 tb setup? Also, what cam are you running and what kind of power numbers? I think I might go that route if I can afford it

btw i cant seem to find the 454 tb anywhere. Is that a junkyard/ebay item only?

 

Well the vortec heads are on my brother's camaro, thats currently carbed untill he gets some funds and motivation to swap to either TBI or Stealth ram. He's running a tiny cam, 204 214 that he had in his 305 before it bit the dust. He's had some problems getting the air cleaner to clear his hood. Right now he's running a drop base with a 2 inch filter, and it just clears the hood, and the throtle linkage just touches the bottom of the cleaner. There are a ton of articles detailing what it takes to run the 454 TB, just keep in mind it's not a bolt and go affair.

As for power. I'm running high 13's with the combo in my sig. Even though my cam has 12 deg more duration my bro can pull hard on me from a roll. I can still pull a car length down low because of better suspension on my monte, and I have a ton more bottom end torque from the FI. I'm betting he's making just over 300 hp and would run mid 13's. With a hot cam, and gears, he'd be breathing on 12's and 400 hp.

With all this said, you really need to look into learning the ropes of chip tuning if you want to do more than a couple of bolt on's. I have a LOT of time rapped up in tuning my car. It's fun I love it. But some people don't have the patience. You need to take a step back and decide what you want.

 

Its tough to say which route to go. I could spend under $1000 for 300 hp and be done with it but im not sure.

Was your brothers hood clearance issue due to the rpm intake or the carb? I have the stock hood (not the one with the "formula bulge") and I was thinking once I get vortec heads, rpm vortec intake, and 454 tb that my 3in Open element would be hitting the hood.

Also, if the perf rpm doesnt hit, will the air gap manifold hit. Air gap seems to flow better and costs only a few bucks more.

I plan on just getting this setup (as long as it fits under my hood)
-vortec heads (regular lift) $520
-vortec air gap (or perf rpm) $225
-454 tb $??
-LT1 cam $100
-full exhaust $1000

should be good for at least 300 horses and this way I wont need new fuel pump, stall and other misc parts to deal with high hp.

 

LT1 heads do NOT have identical ports. Infact they're rather different. The Lt4 heads have more in common with the vortec heads than the Lt1's, only the vortec heads have rather pathetic exhaust ports compared to both. The Lt4s had the taller intake port just like the vortec design. The Lt1 intake won't even seal up the vortec heads!
I'd say stock for stock the Lt1 heads will make more horsepower than stock vortecs. The Lt1's need a balanced port job while the vortecs only require heavy exhaust work.
To sum it up; Lt1 cam with vortec heads is going to make the same plus or minus 10hp than the Lt1 engine.
You should be able to find complete Lt1 engines for less than $4000. You can get a complete LS1 with drivetrain for that much. Which I recommend going with instead of the Lt1.
So expect like 280ish horsepower with the vortec heads and lt1 cam on a gen 1 350, maybe 290 if you do an awesome job with everything else.
I'd skip the lt1 cam and go straight for a zz4 or hotcam. The XE274 works awesome with stock vortec... I mean REALLY AWESOME. The XE28_ with ported vortecs will get a f-body into the high 11's.
Which brings me back to skipping the Lt1/Lt4 swap and going straight for the LS1. Those motors are the cat's meou. The heads and intake flow and produce power like a well built gen 1 and 2. Just add a cam to the LS1 and you're doing things you could only imagine with the older engines.

 

an engine swap is pretty much out of the question. Im trying to stay under $2500. I already have a decent LO5 block with less than 65000 miles on it. Top end work is whats left to do. If I were to do an engine swap then id just do a car swap...to a 4th gen. Thats what my whole thread is concerning...LT1 4th gen or keep my 3rd gen.

what kind of lift does the XE28_ have? Sounds like it would fit with the summit high lift vortec heads. So ive pretty much heard that the perf rpm is the best intake to go with. And im guessing to stick with the 454 tb.

So now that cam setup should be good for close to 400hp? By 11sec did you mean in a 4th gen or 3rd?