89fbrestor

i just bought an unfinished motor project and I'm hoping to get some insight on the heads i have. my block is a 4bolt main, flat top piston, .060 over. it came with a set of 194cc Chevy heads that has had a valve job but i don't know if it's a 3 angle or not. i have a set a set of vortec heads and my question is, even if the Chevy heads have a 3angle valve job(I'll find out) would my vortec heads still be better. putting them side by side the vortec heads intake ports are about .300 taller on the intake and neither heads have been port matched yet, which i do plan on doing. i know i can get a higher cam lift then stock with the vortec heads with the beehive (i think thats the right name) springs. I'm not a gear head but i know enough to build a decent set up i think. my goal is 400hp. i have a build i can follow off of chevy.com which would yeild 440 with the vortec heads but would the other heads get me more hp. sorry if i sounded stupid with any of this just wanted some opinions.

thanks

IROCtheThird

iTrader: (15)

Is there a casting number on them? 194cc is a pretty decent size port considering vortecs use 170cc intake ports. What size valves do they have? Factory vortecs are limited to there 1.94/1.5's, also if you want to run a bigger cam on the vortecs you need to have them tapped for screw in rocker studs but the same could also apply to the other set of heads. There is so many different factors that without a casting number from both its hard to say.

89fbrestor

ok casting #'s
vortec 12558062
chevy 8998993 GM 49

those are the #'s. i thought for sure the vortec would blow away the chevy heads from what i was reading on some of the magazine websites i'v been reading. thanks for the input

Atilla the Fun

993s are smog heads. way inferior to stock vortecs. Vortec heads are not limited to 1.94/1.50 valves, I've done the 2.02/1.60s myself. But there's no point touching the intake ports other than gasket matching.
The 993 heads won't get you to 400 hp. And they're more like 164cc. But the 993s will let you use regular unleaded gas, while the compression you'll get with the vortecs will be over 10:1, and possibly close to 10.5:1, so you will need a too-big cam or premium unleaded gas. Vortecs have good octane tolerance, but it's not that good.

89fbrestor

yup i'm lost now lol so if i went with vortec i would need a big cam? is there a website anyone know about that would give me some suggestions on cam combinations for either head etc........ i dont know where to begin. i hate to be an idiot but i really thought it would be an easier decision.

Atilla the Fun

sorry for confusing you.
No, you'd need premium unleaded, not a too-big cam.
Whatever cam you choose, the vortec heads will give you at least 30 more horses.
If you like that 440 hp build you mentioned, then copy it exactly.

F-Body Demon

iTrader: (1)

993s in the right hands can be ported for good power...but they crack easy. Stick both the vortecs!

89fbrestor

ok so if i polished the bowls, milled down the valve guides for better springs and did a port match and polish job. i could skip the machine shop since they came factory with a 3 angle valve job if I'm not mistaken and i'd be good to go right? i used to work in a machine shop so i know how to do that stuff and i have the epuipment. is there anything the machine shop will do that i could'nt? and i was told a cam in the area of 222-228 wold be about right for 400hp. have no idea what those #'s mean for the cam but i'm sure summit can get it for me lol anyway thanks a ton for the info.


thanks
brian

Atilla the Fun

I told you, the 993s, even ported, won't get you to 400 hp. With the vortecs, all you need is GMPP's "HOT" cam kit, assuming you use an '87-up 350. Top with an Edelbrock RPM AirGap, use headers, you'll have 401 hp at 5600 rpm, 428 tq at 4200 rpm, and over 385 tq from 2600-5400 rpm.

89fbrestor

lol oh i'm not doubting what anyone says i love to hear all sides of things so i have a better idea when i go research it. i looked on the back of the motor for the casting number and it is 4088548 as i was curious about what you said for the year of the block and now i cant find that # on line. the only thing i found is that it might be a marine block somebody please tell me i'm not screwed lol

brian

InfernalVortex

iTrader: (4)

Run the numbers on mortec.com

Also, the 993's aren't worth bothering with. Use the Vortecs. Do what you need to make them work, they're excellent heads.

I also dont see how they'll pu t you into the 10:1 range. Closer to 9.5:1 probably, just like any other regular 64cc head with flat tops. Ive heard people claim the Vortecs have closer to a 61cc chamber, though, but I never CC'd them to know for sure.

And you dont need ab ig cam. In fact really big cams with Vortecs arent necessarily a great idea because vortecs dont have giant intake ports and they're valve-lift limited unless you do some clever valve spring work or machinework to make them handle high lift cams. They also stall around .500 lift if Iremember right. A medium cam works best in them for various reasons here, a more reasonably sized big cam would work well too, but really if you're getting cams into the .550 lift range with durations in the 240s plus the Vortecs will be the bottleneck.

89fbrestor

checked the #s on mortec. it is an 86 to 88 block. and ya I'm going with the vortec. been reading and talking to people all day. I'm going to do the bowl blend and port and polish myself, I'll use the beehive springs and get a decent cam. doesn't have to be a beast but if touch that 400hp mark I'll be a happy camper and from what I've been reading today i should get just a little over the 400hp mark so all is good . I'll take some pics of the build tonight and post em so everyone can what i got going on. thanks so much to everyone for the input. i love my camaro and this web site lol

brian

89fbrestor

thats the new motor replacing the 305.

Atilla the Fun

Let me walk you through the math:
4.060 bore, 3.48" stroke, swept volume is 738.4 cc. Assuming the pistons are 1.560" tall as they should be, most F/T 4VR pistons are 5 to 6 cc . We'll go with 5. The Vortecs really are closer to 61cc, so we'll go with that. Now, if the block hasn't been decked, the pistons will be at least 0.022" below the decks. The volume of that, with a minimal chamfer, is 4.7 cc. Now, a head gasket. for proper quench with an un-decked block, the only correct choice is Fel-Pro steel shims, advertised as 3.2cc. Now, add all that up, divide it by everything but the swept, the static compression is 10.992:1
Now, that's the high side. Let's try the low side. Head at 63 cc, deck volume at 5.5cc from pistons about 0.026" in the hole, pistons at 6.1cc, but still use the fel-pros. Then the result is 10.491:1

Atilla the Fun

The world needs more green camaros, I'll be awaiting more pics when it's all reassembled.

89fbrestor

ok that last one was way over my head i even put my hand up to catch it and still missed it........ was it a wrench in plans. after all the reading i did today i was sure the vortecs were the right choice. bowl blen, port match and polish, tapped rocker stud and good to go and i would need premium unleaded gasoline. which i would want to run in a nice motor anyway. does all this still work?

89fbrestor

have faith it will look good

Atilla the Fun

Choose a cam that has no more than 2 degrees of overlap at 0.050", no less than -4 degrees, and has an intake valve closing no earlier than 40 degrees abdc at 0.050", and then you can run Vortecs with pump gas using a flat top piston 350. But on really hot days you may need a bottle of octane booster. You'll also want a 3.42:1 or 3.73:1 gear, and a 2400-stall converter. Your shift point will be 6000 rpm.

89fbrestor

good info thanks on that one.

89fbrestor

quick question to add to this tread. will 400hp be a problem the the lower end not being forged?

F-Body Demon

iTrader: (1)

What does your bottom end look like? Stock gear or upgraded parts? Stock rod bolts in newer blocks give up at 6k older rods go further. Stock pistons havn't been known to last very long at high rpm either...but you said you were .060 over right? So, yeah what are you using?

Atilla the Fun

The LT1s use the "later model rod bolts" and they're dead reliable for 6200 rpm upshifts for over 150,000 miles. I know, I've done it.
But that's off topic. I've had stock LO5 bottom ends to 6000 rpm upshifts, reliably, for most of the last 10 years. 420 HP with Speed Pro hypereutectics is virtually guaranteed safe if you keep it free from any detonation.
420 hp with stock cranks is fine, too.

89fbrestor

ya stock crank and rods, just new pistons. plus i dont plan ever putting slick on there and hitting it hard or anything like that. its just for street and to beat the average joe who wants to race me cuz of my tun er style paint jobs lol