Roller-cam Vortec 357 TBI build

[woody80z28]

I'm in the middle of an engine build and thought I'd post up my progress so far.

My truck was gutless so I figured I'd build it while the trans was out. Upon disassembly I found out the previous rebuilder used #187 305 swirl port heads and mega-dish pistons for a pathetic 8.7:1 CR and choketastic valves. On the bright side though, the engine was very clean and the machine work was recent...the cylinders look fantastic. So it's a good starting point.

Since the block was roller-ready, I'm installing a stock Camaro LT1 cam that I got for free (203/[email protected], .447/.459, 117), Vortec heads, Edelbrock Performer intake and Keith Black 12cc pistons for 9.7:1 compression. I also did the Ultimate TBI mods and installing long tubes with a Catco converter. Figuring about 300hp@4500 and 400tq@2000 as an educated guess.

Between the extra power from the engine build and the extra gearing from the 4l60e to NV4500 swap it should feel like a whole new truck!

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[zayres29]

Very nice I would like to start building an engine as well for my 91 soon

 

[MOBS]

Just curious, but did it ever cross your mind that the cam you chose may be a tad small? Ofcourse being free is very tempting also

 

[woody80z28]

Just curious, but did it ever cross your mind that the cam you chose may be a tad small? Ofcourse being free is very tempting also

It's quite a bit bigger than stock...by about 10deg and .060 lift. And it will keep the power right down low. Should be an off-idle monster.

 

[woody80z28]

If you have three Chevy 350s torn apart in your garage...you might be a redneck. haha

First set of Vortecs I got were cracked, so I grabbed another pair today and they look much better. After the hassle of pulling a junkyard engine out in a field they better be!

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My garage looks like I'm a hoarder.

 

[MOBS]

Well, from one hoarder to another hoarder: "Atleast your's is nice 'n neat!" Mine hasn't seen a spring cleaning since spring....with my collective abilities, I needa cleaning for every season!

But I do like your shop though.....engines in the bare, mmmmmmm....like a teen in a tittie bar! HAHAHA

 

[Chris]

Hate to burst your bubble, but you're looking at 250hp MAX out of that combination, and that's with a custom tune.

Now if you threw your stock fuel pump in the trash for a Walbro 255 and melted the stock throttle body down into a trinket in favor of a unit from a 94/95 7.4L, the stock injectors would be able to actually fuel the engine properly if you're well versed in tuning the later OBD1 systems. :read:

 

[woody80z28]

Hate to burst your bubble, but you're looking at 250hp MAX out of that combination, and that's with a custom tune.

Now if you threw your stock fuel pump in the trash for a Walbro 255 and melted the stock throttle body down into a trinket in favor of a unit from a 94/95 7.4L, the stock injectors would be able to actually fuel the engine properly if you're well versed in tuning the later OBD1 systems. :read:

I am upping the fuel pressure and tuning it with my Autoprom. I actually have a Walbro 255 sitting around waiting for my EFI conversion on the Camaro that I could use. From what I have read, the stock fuel injectors still work well up to about 25psi...which would be about double the lb/hr they are now. Granted I haven't actually done this yet, but I don't see it being a big problem and should be fine. I guess we shall see.

A stock Vortec 350 is rated at 255hp, and my engine will have more cam, more compression, headers and a more traditional intake. I know it will be over 250.

 

[MOBS]

Have you gotten that modded tbi bench tested for airflow yet? The highest I've SEEN someone run those stock injectors were 18, so I wanna see this But yeah, your stock fuel pump will really need replaced, just for something a little more reliable at the psi you're wanting to run.

Oh, do you happen to have a spare camel hump head around that doesn't have a match? Need a 3rd Gen head, someone jacked one of them out of my shop the other day, so I'm left with one. Maybe i could build a HOT 4-cyl with it, lol.

 

[woody80z28]

Damon over at NastyZ28 is pretty knowledgeable about early GM EFI and said there would be no problem with fuel supply from the stock injectors at a higher pressure. I'll probably keep the Walbro for the Camaro and just put a TPI pump in the truck.

One camel hump head will work fine for a boat anchor. Two would be overkill. haha