I have a 350 i am planning on building soon and was wondering about some combinations. Here's an idea of a combo i was thinking about doing. Does anyone have any ideas about how much hp, both flywheel and rwhp, i would make with this combo?

350 Bored .010
191 Heads w/ pocket porting 1.94 in/1.5 in
9.5:1 compression ratio
non-cc qjet
Edelbrock performer intake
comp xe256h cam
256 int./268 exh.
valve lift: .447 int./.454 exh.
lobe seperation 110
shorty headers w/ 3in collector and y-pipe and cat back exhaust
t-5 tranny
3:23 gears

Comments? Questions? Suggestions?
Thanks in advance guys

 

What's a 191 head? Where did you find 4.010" pistons?

 

If those 191 heads are those swirl port POS's get rid of them pocket porting can't make performers out of thise turds. Other than that, your combo sounds alot like mine. I would say go with either the xe262h or the xe268h cam instead though. The xe256h is barely bigger than stock. you'll notice the difference but you'll want more. I have the 262 and I still want more.

 

Well they make .010 rings that you can get, but i might end up just getting it bored .020 for a better fit with new pistons

and yeah, i'm pretty sure they're swirlies. Are they really that bad?

Oh btw, i'm looking for between 300-350 rwhp. (if thats possible without breaking my t-5 lol) so i'm not going for a strip car. its gonna be a daily driver so i don't want anything too big. i just want some good power and some good torque lol

 

Yeah those "swirlies" are that bad. Pick up a set of junk yard vortecs, or find some 083 castings or something like that. The swirl port heads quit making power at aroun 3000 rpm. I had them on a 350 that I pulled from a mid 90's van and put in the camaro. I could floor it and give it all i had and it still couldn't pull hard enough to to keep the trans from shifting at 3000 rpm. they'll never make 300-350 at the flywheel.

 

dont have a flow profile for those heads but the closest I could find and this seems a little over rated says around 280 hp 320 ft torque at the flywheel

 

Dang. That is pretty bad. I think i'll have to try and find a better set of heads now. the only problem with vortec heads is the manifolds for them are a little more expensive and i would have to get one if i got vortec heads. I really don't want to spend a lot on heads if i don't have to and i don't really have a lot of time to go to the yard to pick some up but i'll see if i can't find some that someone will sell me for pretty cheap. Any certain ones i should look for?

 

You want the vortec heads that do not have the hardened inserts on the valve seats. There is no casting number that will guarantee that you don't get those heads. The non-inserted heads flow better. That being said, I have the heads with the inserts and they perform great as far as I can tell. You just have to look at the heads to tell. Good luck. I don't know which non-vortec heads are good. I've heard the 083's are good but they are hard to come by. Vortecs would be the easiest to find and identify, but you're right, you would need a different intake manifold. The manifold for your q-jet is about $175.

 

Yup. About $50 bucks more than the normal one. of course i guess it'd be worth it for the power increase i'd get. But realisticaly speaking, there's no way i would be able to get between 275 - 300 rwhp with the swirlies? My main goal is to have something that will give me the most hp and torque i can without blowing my t-5, though eventually i plan on upgrading to a t-56 anyway.

 

With swirl port heads and the GMPP HOT cam, you can expect 306 hp at the flywheel. They truly suck a$$. Even 882 heads are better than swirl-ports. for comparison I also had an '882-headed 350 put out 353 flywheel HP with the GMPP HOT cam. But that was with flat-top pistons, a little of my own porting, and an RPM AirGap Edelbrock intake.

 

Bottom line, get rid of the 191's and find something else.

 

haha yeah thats what it seems like. I'll have to look around an see if i can't find some vortecs. Maybe i can steal the ones off of my brothers truck lol. But i'll see if i can't get some vortecs or some better stock heads i suppose. Well, there goes more money, but i guess it's money well spent.

 

Well i found some remanufactured vortecs for $420. and now, my plan for my rebuild has kind of changed course.

The block will be a 350 bored .030" over
I will probably get the 062 or 906 vortec heads and an edelbrock 2116 performer dual plane vortec intake
quadrajet carb
comps xe262 cam
hedman 68470 headers? (still haven't completely decided on headers yet)
and a magnaflow cat back exhaust which is already on the car.
and about a 9 to 9.5:1 compression ratio is what i'm going for.
Can anyone tell me about how much hp this combo would give me? Thanks guys.

 

Okay, well I got the machine work done and its now a 350 bored .030 over (355) and I just ordered the cam today. The xe262 from comp and I'm still planning on getting a set of vortec heads and the edelbrock intake.

Oh, and btw, I discovered that the heads that were one the engine weren't even a pair. They're two seperate heads. One has the casting number 083 and the other has the casting 191. I'm not sure how I didn't realize this before though But this means that i'm definitely getting a pair of vortec heads

 

It's too hard to say, not enough details. Stock crank? What size, design, and material will your rods be? What will the pistons be made of? Cast internals will rob a lot of your power right from the git-go.

I honestly don't know dude, it's too vague of a question, with not enough details. The XE256 isn't really meant to rev sky high, so your only hope of seeing decent HP numbers would be to make a massive amount of Torque.

Let's say that 350 of yours can produce I don't know, 230 FT.-LBS. @ 4,300 RPM. That = 188 Horsepower.

260 FT.-LBS. @ 4,500 RPM = 222 Horsepower.

If you want a nice 300 Horsepower at around 5,000 RPM with that cam, good luck with producing 315 FT.-LBS. of Torque with that setup (which would be quite easy) BUT carrying that amount of Torque up to 5,000 RPM with that specific cam.

300 Horsepower X 5,252 / 5,000 RPM = 315.12 FT.-LBS. of Torque.

Seriously, go with a different cam. I'd recommend the XE268H for you. You'll be able to carry Torque a bit higher into the RPM range, but depending on your compression that you'd want to run, you'd have to play around with timing a bit more with that cam.

Disregard that, I didn't notice your post about already ordering the cam.

 

Well the crank is cast and the mains and rods are oversized .010. The rods are the stock rods, and the pistons are cast as well. And i'm not going for 400+hp, i only want between like 300 and 350. And the cam i chose was the comp xe262, right in between the xe256 and the xe268. The reason i chose it was that its supposed to give more torque than the xe268 and still deliver a good amount of hp.

 

I'd really hope that if it produces more Torque, your peak HP numbers would be higher. Otherwise, it's one sh!tty cam that can't keep the intake velocity up over a wide part of the RPM range.

Torque and Horsepower are not different ways of powering a vehicle. Horsepower is directly derived from Torque, and RPM.

 

It's a good cam, but Vortec exhaust ports are crappy compared to the intakes. With Vortec heads, much more exhaust duration is necessary.

 

Until you provide info, I'm calling BS on 10-over pistons for SBCs.

 

I think when i posted that I may have been thinking about rods instead of pisons. Idk.

 

And from what i've read, the way the cam is designed is to give you more mid range power which is more of what i'm looking for. As far as heads, the vortecs are a lot better than what i have now, which isn't even a matching set of heads, plus i can get a remanufactured set of vortecs for $350.

 

Street builds should have tQ numbers that are equal to or greater than the HP number. Race engines can have HP numbers bigger than the TQ, but that comes from having the RPM range too high.
Huge cams and huge heads together will get you those big HP numbers, but not enough streetability. If you want big HP on the street, keep the cam modest, then add boost.

 

Just keep in mind that there is a reason that they never put that t5 behind a 350. It isn't rated over 300 ftlbs and won't last long if you thrash it. Vortec heads with a xe262 cam and that exhaust is going to make some nice torque and early so don't be dropping the clutch too high, you shouldn't need to anyway.

 

Thank you for the elementary lesson, father. I did not know that.

Not every single street build will have the characteristics that you speak of. 5,000 RPM is practically the magical number. If your cam can provide the flow to carry a bunch of Torque past that number, you'd have the overall big HP numbers.

With a higher RPM stall, I see not a single reason why you couldn't run an engine on the street, that's producing peak power at over 6,000 RPM. Comp, and other reputable sites will recommend 3.73's+ on a manual or a higher RPM stall Torque converter on an automatic, but it's really not necessary in the case of a manual. If someone doesn't have the feel of their clutch down enough where they cannot get going by 1,500-1,700 RPM without stalling, or screeching the tires a bit, they should not be driving a stick. Despite what cam they're running.

I'd personally run a stock cam on all forced induction builds. It's called forced induction for a reason, that air is being forced in there by a compressor. There's no need at all for insane amounts of lift. Valve overlap on an F.I. setup = very unefficient.

 

I'm gonna try and make the t5 last as long as possible and i'm not too hard on it so it should last a little while i'm hoping. I'm gonna replace the clutch with a clutch package from zoom probably whenever i pull the 305 out. And, thats more of what i'm going for is more torque than hp. Plus, in choosing my combination, streetability and gas mileage were somethings i had to consider, plus the relatively weak tranny thats gonna have to support it for a little while. I've heard of people making t5's last quite awhile with 350+ hp, so i'm hoping maybe i can as well

 

Here's a estimate from DD2000 for your setup. It's obviously not exact but it will give you a good idea of where your motor will be at. All numbers are flywheel rated.

I just wanted to warn about the T5 before. If you drive it right you shouldn't have any unusual problems. It always isn't 1st that is the problem either, watch those 1-2 shifts and keep them clean when you have your foot in it.

 

okay here is the XR262 specs manually entered with plain jane vortecs and small headers...

XR262 isnt helping at all

 

High stall is the exact opposite of driveability, thus, NOT street.

 

SpitotRS305 your numbers are way off. It looks like you have it setup as seat to seat timing on the cam but entered the duration @ .5. This is a flat tappet block too so no roller.

 

no that cam was entered properly comp only gives timing @.006 you need to enter the duration @.05 and the lift so that DD can calculate based on the IVO/IVC events

it was just the wrong cam

 

Thank you Doom86, and like I said earlier, it looks like that setup will give me a more torque than hp, which is more of what i want anyway. 300-350 is about what i'm going for on the hp range so it looks like this combo should put me right around there. Should be a very streetable combo too correct?

 

It's configured wrong it's set to seat to seat valve opening/closing timing so duration should be entered as the cams advertised duration.

A Vortec headed 350 and a XR262 are going to make loads more HP then 215ish with that setup. It would make more HP then that a LG4 cam.

 

When I had the 350 in my car, I had a mini ram manifold, zz9 cam (which was about the biggest I could put in there and still retain stock valvetrain), edelbrock performer rpm heads, edelbrock shorty headers along with a 3 inch catback, and I had a perfect tune and put down 292 hp to the rear wheels and 318 tq. I don't think your going to be that close to your 350 hp at the wheels. When the t5 goes, instead of rebuilding, put a t56 instead. They can be built to handle gobs of power

 

you do understand that DD2003 is calculating that duration @.05 based on valve events...
Here is another example.. a stock cam file from DD2003

you might notice that the grind number is the same as the XE262
but wait the durations are that advertised oh no....

it only reports the .050 duration because that is what is actually important

 

Well my plan is to drive it with the t5 until it goes out, and then, yes i will probably swap to a t56. And, i'm not going for 350 hp at the wheels, i'm going for 300-350 at the flywheel.

 

But also note that you have it setup right this time and that "valve opening/closing based on:" is set to .050-inch and not seat to seat like it was erroneously entered in the first calculation. In the previous image you can clearly see it's not calculating .050-inch lift at all, it's stared out, and it's thinking that 211 is the advertised duration.

Just use logic the flat tappet cam of same duration and lift is making loads more power then the roller cam according to your calculations. Something is off and that is all that I can tell.

 

okay this is a very simple concept...

when desktopdyno goes to calculate a cam it needs

1 the advertised duration
2 the intake centerline
3 the cam lobe center angle
4 the lift at the valve with the assumption of 1.5 rockers

now if you know all of those and also know that the cam manager in DD is setup with compcams grinds in mind you set your ramp rate to 3.0 for the flat tappet

now it will calculate your seat to seat valve timings almost perfect for comps grinds

the only reason to need the .050 numbers is to calculate ramp rate properly however a perfect ramp rate calculation isnt very important 3-4HP at most

here is the XE262 again where the secondary .050 numbers arent used instead i let DD do the math and guess what pretty damn close...


the problem with my first run was the fact that the XR262 is a VERY VERY different cam so EXTREMELY different that it isnt even a chevy grind... think Chrysler

and DD2003 doesnt do neg. degrees very well