Hey guys,
Just as the title says I have a 350. It was the gm290crate motor but I did some changes

Xe268 can
600 cfm edlebrock Carb (1406)
headman headers
rpm intake manifold
hei streetfire distributor

I will changing the heads out to a 64cc fast burn heads

I want to know what I can expect if I go down the track with my current set up. Its in a 86 Camaro 5speed 3.42 posi rear I believe is in there. I will also like to know if my Carb is typiaclly rich or lean from the factory and witch way I should go with it.

In the near furture I would like to get this car in the low 13s high 12s . What would you guys do to get there with this set up?

Oh and this car is my second car so its not a primates car but I do drive it all spring summer and fall. I will drive it to work but its mainly a car I'm going to be ripping around in and taking to the track.

 

Change to a 750 cfm carb when you change the heads. Forget the GM "Fast Burn" heads, you'll get better results with any of the 180 cc heads. Right now you have too much cam for that engine, which is in fact not 8.5:1, but is no better than 8.0:1

 

That sucks .. I called summit and spoke with there tech line and told them exactly what I have and that's what they recommended to me.

Were do you think the power is at now and were do you think the power will be if the compresion was closer to 10.1?

 

Get the Trickflow 175cc heads with 56cc chambers. They flow 242cfm and will give you a good bump in compression.

 

This is also one of the better ways to get near 10.1:1, because 64 cc heads with those pistons is not going to get you anywhere close to 10.1:1

 

With the trick flow heads being 56cc will I be able to run pump gas?

I was thinking more along the lines of 64cc chambers and a thin head gasket

What would the power be with heads and a 750 Carb I will probably get a quickfuel or mighty demond carb

 

You need to understand the effect of DCR
read
http://cochise.uia.net/pkelley2/DynamicCR.html

The " bigger " the cam the less "real " CR you have.

 

Sounds great ill read up on that about the real CR.

Now this is the one thing that throws me off. I plugged in all the propose numbers into summit racing compression calculator based off of all the information that came with my engine

it said if I got 62cc chamber with a thinner head gasket it would put me at 10.5 aprox CR

When I plugged in the 64cc heads and same gasket it came to 9.75 cr

How can I properly caluclate CR and know that will be correct?

 

Download and install this calculator ;
http://cochise.uia.net/pkelley2/dcrvb6.zip

does static CR and if you have the cam specs DCR as well.

The calculated CR will only be as good as the info inputted .
On some of the inputs , a minor change can makes a major adjustment to the CR .So to be truely accurate ,you need the exact volume of the dish in the pistons ,the actual deck height , the gasket bore and thickness.

 

I have the 56cc Trickflows with a Blueprint 355 shortblock and XE268 cam and I run premium pump gas. My compression is 10.25:1 no issues.

 

What Lind of HP and tq are you putting down with it?

 

Kind of *

 

Keep in mind im running aftermarket TPI so my torque numbers will be big and HP down a bit from carb. Its going on dyno end of the month I expect to pull just over 300HP at the wheels which would be maybe 360 at the crank. However over the winter im switching to HSR intake so I expect another 40hp at the wheels with that swap. I also have longtube headers, no emmisions, underdrive pulleys etc.

 

Okay so I should be in the low 300 area then?

What's the deal with... that one article that magazine did on the xe268 can with the gm290 crate .. they got it over 400 to the flywheel.

That should bring it some were around 365 to the wheels right?

How can they do that with less compression? I they put on 64cc heads (rhs I beleove) and 180cc chambers and was able to put down low 400 HP and tq

Before I was just trying to copy what they did but with higher compression I should be to achive more HP and tq right?

 

That is not a super heavy duty cam, you can go 750 but I think you are overdoing it a bit. A 600 or 650 will run it just fine.


Although do what you want, personally I know way to many people who went with a 750 and regretted it.

Here is comp cams dyno of that cam

http://www.compcams.com/v002/Pages/388/XE268H-10.aspx

 

Yea I did see an article online about The difference between 600,650,750,850cfm carbs. They saw the biggest jump in HP and tq going from 600-650 then after that the 750 and 850 only gained about 2-3hp on the peak

I forget the articei wanna say it was done by carcraft or super Chevy I think the other one is.

I'm probably going to end up with a 650 or maybe a 670 Holley I have to do research before spending money on them.

Were do you guys think my car is at now power wise? I'm just asking for a ball park because I haven't had it dynoed yet but would like to know if I'm right were I am supposed to be or if something is off

Last time I took it down the drag strip I ran a 15.1 .

I was pretty posted but at the time my floats weren't set right and was pumping fuel threw

Since then I have fixed the floats but haven't gotten a chance to open it up yet I'm expecting I should be around 14.5 ish?

 

15.1 maybe 225hp

 

Alright so I'll double check everything and take it down the strip soon and. Get a time. So if I'm in 15-14.5 ball park I'm in the right area.

 

Ok great. Now last question I have. Sorry I feel like a noob asking these questions.

How do I know how far I can push the motor for instance.

If I run 10.1 compression how much room do I have left for a supercharger /Turbo

I guess what I am asking is how you the limits of. Internals of the motor and if switching to aluminum heads how does that effect the limits of the engine?

 

Just ran a simulation 245hp and 345 tq gave me a 15.0 with your trans and rear.

Running 10:1 compression and a turbo or supercharger will result in a blow up engine.

 

Ok so no boost.

What simulator do you use? I would love to use one to see what adjustments will be effect the motor.

Can you run the same set up with 10.1 cr?

 

The same setup with 10:1 compression but the same HP would not be any faster.

Dynosim and Cartest should give you ballpark numbers

 

Ok cool thanks.

 

No. Those articles use a lot of fancy pants tomfoolery to inflate numbers. They measure hp the same way GM rates that goodwrench 350, which is mostly magic numbers from the trashcan. The Goodwrench 350 makes 160hp to the wheels on a good day. That 400hp one probalby has new heads, massive headers, single plane high rise intake, huge carb, and isnt even turning it's own accessories. 400hp in an article is much closer to 300hp in real life with stuff you can actually fit in the car based on the same scale the factory uses. rwhp is is going to be closer to 200. Maybe 250.

I would imagine with what you have youre making around 200hp now. With the trickflow heads they mentioned, you MIGHT be able to get the compression up enough and get your flow high enough to hit 325ish hp at the flywheel depending on many other factors. With the right gearing and tires that's low 13's and in one of these cars, 300hp is good fun without blowing up stock drivetrain parts constantly.


Boost is one thing, and not a bad idea for low compression engines like yours, but there's no way a goodwrench 350 bottom end is going to put up with forced induction very long. turbos are cheaper, require lots of fabrication. Procharger type superchargers cost enough money that you're a lot better off doing an LSx swap in the long run. If you want to play with turbos and build a turbo system, a goodwrench 350 is one of the best engines to experiment with to learn how to do it, because they're cheap enough you dont have to worry too much about blowing them up when you get it wrong.

 

Now I am thinking what will make more power. Should get like a weiand 144 or 177 supercharger and port my stick heads and upgrade the springs ?

Or get new heads ?

I'm kind of hating this 290hp crate I feel like I should have purchased a short block and put the heads I wanted on it.

 

Stock*

 

What are your goals for this engine?

 

A fun weekend car. It does get driven a lot in the summer but I will love to take it to the drag strip and run low 13s in if not upper 12s I will be happy with that and stop there

 

What number did you enter for the deck clearance? What did you put in for the dish volume?

Your motor was around 8.1:1 AT BEST out of the box. (4.000" bore, 3.48" stroke, .025" deck clearance, .039" gasket, 76cc heads, 12cc dish) That's not enough compression for the cam that's IN IT, let alone any kind of "performance" "high-RPM" cam. PLus of course the deck clearance is NEVER any less than .025", but is OFTEN more than that, and ALWAYS varies extensively from one cyl to another in a stock build; so you'd be LUCKY to see 8.0:1 on all 8.

58cc heads (305, such as 416 casting) will bring you to mid 9s. That's fine for iron heads, marginally still not enough for aluminum ones.

As a platform for a "performance" build, that is one of the worst possible engines to start out with. Just not a good choice. All it is, is the "260 HP" motor with a different cam. Still, the same heads, pistons, etc. that produced the 160 HP wonders of the 70s, PART # FOR PART #. But I guess it's too late to worry about that now; can't reach back into the past and un-buy it; gotta concentrate on what to do, moving forward not backward.

First thing I would do if I was forced to accept one of those things, is put some better pistons in it. I'd be looking at flat-tops that DON'T add the usual "rebuilder" extra .020" of deck clearance, and to get the block zero-decked at the same time. But of course one of the things you overpaid for by buying that, was the warranty; which of course, is out the window when you tear down the short block. But I guess ya gotta do what you gotta do with what ya've got to do it with.

There's NO WAY it will run low 13s, let alone 12s, as it sits now; short of 200 HP of nitrous. That's fantasy land. Go run it right now and see what it does. Realize that at 100 mph or thereabouts, the kind of speeds that a 12-second car should run in the ¼, one second = 160' roughly. So if it's a low 16-second car right now, which is about what it should be, it's over 500' behind a low 13-second car at the stripe. (leave at the same time, and the low-13 car crosses the stripe when your car is still more than 500' from it... doesn't even look like a "race" at all, considering that the track is only 1320' long to begin with) You've got A LONG WAY to go.

AFAIK no 86 car came with 3.42 gears but I could of course be wrong about that. Probably has 3.23 gears in it. But that's just idle speculation anyway. You should already know that though, having changed the rear end fluid and all, as any sensible owner would already have done; what did you see while you were taking care of the "deferred maintenance"? Whatever you saw, THAT'S what's in it. I'd go look that back up in your notes you took, and go from there.

 

You're friggin hilarious, man

 

Just put a set of good heads on it and a 650 dp carb and it will feel like a different engine between the increased flow and compression.
As for a head suggestion... I would probably go with a profiler 185cc
http://www.profilerperformance.com/r.../sbc-23-degree
Should run 12's with a tire with no problem

 

I checked my rear serval times close to 3.5 shaft rotations per one tire rotation

I no the car runs right now 15 seconds not 16 but thanks any way.

As far as the compression valuator I don't wtf I'm doing with it to be honest I'm trying my best to figure it out that's why I am asking for help here.

So what would make most power blower? Or new heads and pistons ? And a 650 carb?

Jabot
Thank you I'll look into getting those heads what about the 650 avs thunder series ?

 

a blower will make more power, but its real easy to blow up the engine if you can't tune it! So I would not recommend that idea.
I am not a fan of edelbrock carbs personally. I would get a 650 dp holley or holley style like a proform or quickfuel.

 

Okay sounds good quickfuel was one of the ones I was looking at as well.

What about doing a piston swap because I am probably going to pull the motor out over winter so I can respray the engine bay. Would I have to re-balance the rotation assembly afterwords as well?

 

Im not really a hardcore racer kinda guy, and I've got a carb on mine but I usually just wish I had the money to put EFI on it. But I dont really see the advantage of something like a quickfuel carb over a Holley. Aren't they just basically Holleys that are shinier with some anodized metering plates? I mean I think they will have 4 corner idle adjustments but that kind of thing just isnt that important to me to pay the price difference.

 

No they are not just shinier, they are calibrated better out of the box and the main reason most metering blocks and base plates are made out of billet now is because they are less prone to warping like the old holleys are. Anyone who had a holley back in the day that kept blowing out metering block gaskets knows about that.

I don't know where you get your prices from but the holley's are more expensive for the same or even less features.
Holley classic 650 dp 0-4777S $426
Quickfuel HR-650 $417 (and has many more tunable features and billet parts)
Proform 650 dp street carb 67212 $428 (basically same as quickfuel hr)
Holley ultra dp 0-76650BK $515

 

So the quick fuel will calibrated right out of the box for most applications ?

 

Well nothing is calibrated right in stock form, but for most situations its pretty good.
Just follow the holley tuning sticky in the carb section and it will drive better than most!

 

Okay awesome. My edlebrock I was tuning I got pretty good but i never tuned a carb for a car before but I learned a lot. At least the quick fuel one will be pretty close from the start

 

Im not really convinced you can tune a carb better "out of the box" over hte wide range of applications it will go on. It reeks of confirmation bias. Also, my Holley hasnt warped any metering blocks since I got it 7 years ago. Doesn't really seem like a big problem to me.

Clearly the nicer carbs are going to be shinier, perhaps machined more accurately, have easier access to some adjustments, etc. But they're still just fancy Holleys. But then again, I buy half my tools from Harbor Freight...

That said... if you can get the Quickfuels for cheaper, do it. Even me in my crotchety grumpy ways think those Quickfuel type carbs look great, and they're clearly better. I think I paid like mid $300's for my Holley. It was some factory refurbished thing. Worked fine. Still works fine.

 

OK got a set of heads on
190cc intake
64cc chambers
Dual valve springs
2.02/1.6 valves
Felpro 1094 .015 thick gasket
Still the 1406 carb and rpm intake. Stock jets

Only issue I am having it starts and runs great.

If I hit the throttle hard for the primaries I get one backfire threw the intake.

If I roll the throttle Doesnt happen

My timing is at 16*

Now secondarys. I drive down the road once my secondarys open it seems to slow and get a back fire threw the exhuast. And it sputters a little bit before that. Around 3k rpm

Does this all seem like the carb needs to be jetted up? I just want to know what way to get with this so I can drive it. I will be getting a quick fuel 650. I just want the 1406 running decent so I can drive it and open it up a little bit

 

So much missing info

 

Yes those are the pro comp heads

If I roll on the throttle the backfire threw the intakedoes not happen

I am using 93 Oct. Compression is about 9.5:1

No timing is not locked mechanical advance only no vacuum advance hooked up

16* because thats what I read up set this can for between 16* and 14* in that area

This can was in with my old heads no issues only thing that changed were the heads

 

Yes I adjusted jets with vacuum guage I'm getting about 13 in of vacuum needle stays steady around 12 shakes small amount but if the rpms increase it stops shaking.

Maybe valve adjustment a little to tight ?

 

13** sorry I typed 12.
It stays steady at 13. With the needle shaking a little bit

 

13 inches is really low for that cam, but I get about the same on my xe262 350. I finally decided these gauges aren't always accurate, but there could be an issue somewhere. My friend's perfectly good, completely stock Jeep I6 4.0 pulls 15 inches on that gauge and that seems a good 4-5 inches low to me too.

From what I understand my cam should be closer to 18-19 and yours shouldnt be much less than that. So if you figure out something let me know. The needle jumping over a small range is normal, that's just the cam lope showing up in the intake vacuum. Listen to the engine to see if it corresponds well. If it's jumping more than 1 inch very consistently (ie each time through the firing order) it might be a sign of issues.

 

I'll take a look at it again today.

I've been second guessing my self all day about the valve adjustment I feel like they me be a tad tight I think I will redo them today and check the wires.

I'm pretty sure I don't have any crossed wires. Done that to many times to forget to triple check that .

So it should be at 18 initial almost?
I will also check that after the valve adjustment and check vacuum before and after

 

Procomp heads with that cam? I hope you are running 1.6RRs

 

I don't have a stop plate for the vacuum advance yet.

16 initial around 650

My timing curve I put in the mr gasket advance kit with there weights and plate. I put in the black springs (softest) the chart showed all in by 2500 rpm which is what u was told for this can between 2500 n 3000

 

I don't have the 1.6 RR yet they are on my list to get. Right now they are the stock rockers