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HP increase?? 355 sbc heads/cam/intake upgrade????

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camncars

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Discussion starter · #1 ·
I have a sbc 350 (355) with forged srp pistons, pink rods, gm crank, etc., and have put on a set of AFR 180 heads, lunati voodoo 60103 cam w/ 1.6 rockers for a bit more lift, Edelbrock performer Air Gap intake, Coan 2800 stall converter, and a 3.42 gear, Holley street avenger 670 carb, and a built 350 trans. the car runs GREAT. Has lots of power down low and really pulls hard up to the top. I'm guessing it probalblly runs high 12's or low 13's in the 1/4 mile. I originally built this car/set up for a good street cruiser, which it is, but I really want some more power, and think it is a very tame car to drive and is VERY streetable...
Here's what I'm thinking about doing.
-having the heads and intake worked, ported/polished, by a great well known performance shop, stepping up to a bigger cam (voodoo)60104, upgrading my converter to a 3400.

What hp increace do you thing I will see?? What 1/4 mile time increace should I expect (even though I haven't ran the car yet)

to me, this car is VERY streetable, and I want to keep it that way, but don't mind a bit more of a WILD street setup.

Suggestions?????
HP guesses now/after??????
 
#2 ·
I wouldnt' put a 3400 RPM torque converter in it if you want it to be a reaonably streetable car myself, but then everyone has their own definition of streetable too. Personally I would switch to a roller cam to get the additional HP and keep it driveable on the street and and can be done for the same or less money than the cam, head work, and converter probably. A roller cam can keep the nice lower end pull and add a good deal of torque and hp. Hydraulic if you want to keep the power a bit lower, solid if you want high RPMs (6000 -7500rpm). If you don't have good aftermarket rod bolts in the pink rods I would stay with lower RPM range cam and a Hydraulic roller would be my recomendation.
 
#4 ·
i drive a 4000 stall on the street just fine with 4:10s, for your setup i would go with 3:73s and a 4k stall.. i think it will really wake up your car..
 
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Discussion starter · #5 ·
I really like the 3.42 for occasional hwy driving, so that is going to stay. I drove my friends car with a 3500+ converter, you can really feel the engine wind up, but damn, it really makes the car move when you stab it. I could probablly deal with that, or close to it. I'm thinking of maybe sending mine back to Coan and seeing if they could re-stall it to maybe 3200-3400 instead of 2800 if the price is reasonable.
 
#6 ·
dawg said:
youll be reving just to take off with that converter lol.
IMO just get some NOS and use it when ya need it.
125 shot outta wake you up.
Click to expand...
I totally agree with going for the bottle. I am in the exact same boat. Keep your set up just like it is and add a little spray for when you have the urge. The 3.42's and 2800 stall will work killer with the spray cause of the instant torque increase. Now if you got the extra cash then a proper match hyd roller would be icing on the cake!
 
#7 ·
What is the current compression ratio?
3,200 stall is totally streetable with the right rear end gears, and a trans cooler.
I agree about the roller cam.
 
Discussion starter · #9 ·
What kind of power increase would I see with a roller cam??? I have heard alot of good things about the Voodoo cams, that's why I got the one I have. Any specific roller cam suggestions and other parts needed to make it a roller??? The car feels great now, pulls nice and hard through the whole rpm band, just looking to hop it up some more.
I have been tossing the idea around as well about the spray, say a 100 shot or close. Everything is kind of up in the air right now, just getting some ideas on what to do.
I'll be going to the track in a few weeks to see what kind of 1/4 mile times it gets. Any guesses???
 
#10 ·
A roller will usually make 50hp more just to it being designed better, and way less friction.
You will need new valve springs, new push rods, a new timing chain, thrust button, gaskets etc. Same stuff you would need for a flat tappet cam change but a few extra parts.
I wouldn't go over 230* @.050 with your 10:1 comp.
Small rollers with the right combo make good rwhp for what they are.
I think a few people here run a comp 276 hydraulic roller, it seems to be good.
You will want to at least check piston to valve clearance as rollers are usually above .500" lift.
I'd guess right now the car could run anywhere from a 13.20-12.90, I don't really know much about it though...
 
#11 ·
post the cam specs next time, dont make us look'em up;)
233/241 is too much to a 10:1 350

I'd bump the comp to 10.5:1 - 11:1 with alum heads.
power increase on head work depends on who goes the work and how much. Could be 10-50hp.
Cam wise I'd do a hyd roller around 230-236 with 1.6 rockers on the intake.
RPM intake is good, stick a open spacer on it.
HP750 carb
Good fuel pump?
Whats the exhaust like?

Had a cheapy 350 I threw together for a 69 chevelle I had:
It was around a 400hp engine
TFS homeported heads
Bullit 232/238 hyd. roller
RPM
750 carb
200-4R
2500 stall
411s
1 3/4" headers (too big)
Ran 12.30s @ 110.6 without tuning, I believe 11.9s would have happened with more track time, tuning and good weather.
 
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#12 ·
camncars said:
What kind of power increase would I see with a roller cam??? I have heard alot of good things about the Voodoo cams, that's why I got the one I have. Any specific roller cam suggestions and other parts needed to make it a roller??? The car feels great now, pulls nice and hard through the whole rpm band, just looking to hop it up some more.
I have been tossing the idea around as well about the spray, say a 100 shot or close. Everything is kind of up in the air right now, just getting some ideas on what to do.
I'll be going to the track in a few weeks to see what kind of 1/4 mile times it gets. Any guesses???
Click to expand...
As it sits now I would guess it runs some 12.9-13.1 with drag radials.
 
#13 ·
If those are the newer AFR-180 Street Eliminators I'd be interested to see what a pro could do with them. They're pretty good as is.

If you want to go roller cam and you've got an earlier block, it's going to cost a bit. Those retro roller lifters are expensive. If your AFR's were not custom built and were purchased complete then your springs may be OK for a mild roller already. They try to build them to where the springs overlap several applications. It's easy enough to have one of the springs checked though. If you go up in spring pressure you may want to think about going to steel roller rockers if you don't have them already.

If your cam specs are what 502 posted, you can go with a cam grind that is closer to a single pattern. With AFR's and decent exhaust I wouldn't think that you'd need the extra eight degrees of exhaust duration unless you're going to spray it.

One other thing....have you had the carb tuned on a dyno? My 670 was pretty lean out of the box even on a 9:1 355 with fairly small cam..... 65 and 68 jets, 0.031 discharge nozzle, and 65 power valve.
 
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#14 ·
With the alum heads you can run a point of compression easy without denotation.With the efficient runners you would need 4 to 6 degrees split in the cam duration.Always build you engine around the induction system or it will always be a compromise engine combo.Small hyd rollers can make a lot of power if you dont try to get too crazy with the specs.Too much spring and the hyd wont pump up and will clatter and run like crap.I build a 350 based combo at 365 cid.3.56 stroke 4.040 bore 6 inch rods 10.8 compression with Brodix heads and intake ,hyd roller demon carb. 93 octane unleaded 535 hp on the street.My dyno is very concertive.Any thing on the sreet in a stock body 1 gen this is killer and get you in lots of trouble with Johnny Law.
Just my 2 cents worth.
 
Discussion starter · #15 ·
Here are the cam specs now
•Advertised Duration (Int/Exh): 268/276
•Duration @ .050 (Int/Exh): 227/233
•Gross Valve Lift (Int/Exh): .489/.504
•LSA/ICL: 110/106
•Valve Lash (Int/Exh): Hyd/Hyd
•RPM Range: 1800-6200


Part Number: 60103

as stated above, I added 1.6 rockers which makes the lift a bit higher, .5216/.5376
sorry for the lack of info. Car has headers and 2.5" exhaust w/H-pipe
I "street tuned" the carb and went a bit fatter on the jets, if I remember correctly, I think I also put different discharge nozzles and power valve, works great.
The heads are out of the box AFR 180 part number AFR-0918 specs here-->http://www.airflowresearch.com/index.php?cPath=24_25
 
#16 ·
Great profile.Just remember that 1.5 to 1.6 rockers can add up to 4 degrees duration becides the added lift.This can change your cam even more if its on the edge of being too big IE less bottom end torque
 
Discussion starter · #17 ·
New update to an old thread, let's hear some ideas here. I ran few passes at the track and did a 12.6 w/this setup, 3550 lbs w/driver. I'm pretty happy w/the times for the setup. Another idea I also had if I tear down the engine is to go with a smaller head gasket to raise my compression from 10.1 to closer to 10.5/11.0
 
#18 ·
Go to the track and get an actual time and speed.
Seat of the pants doesn't work too well.

Rework the 180 AFR's not a good idea, its a waste of money as they are probably the best they can be right now. A larger cam, more stall and gear will increase 1/4 mile performance. Your carb and intake are just fine as is.
 
Discussion starter · #19 ·
Well, time to bump this thread up. I've had this same above combo for a while now, and now thinking about pulling the motor/trans to beef it up. As I stated, the car ran a 12.6 and is very streetable. I have been very happy with the performance so far, but time to beef it up.
As of now, I have some problems with the valvetrain, I think a couple of lifters went bad, I was crusing for a while at 4000+rpm on the hwy for a long period of time, and when I got off, I noticed some clicking/ticking. I pulled the valve cover off and found that one of the rockers was very loose, I was able to rock it and noticed there was a huge gap between the roller tip and the valve, about 1/8 inch, so I took the rocker off, re-set it and again and it was fine for a few minutes, but it happened again, and also happened to one rocker on the other side. I'm not sure if I collapsed a couple of lifters or what it may be??? I made sure the rockers/poly locks were on tight and didn't just happen to loosen up.???
Well, I'm thinking on pulling the motor/trans instead of just replacing the lifters (if that's the problem)
I'm leaning towards a roller cam/lifters (not sure to go with hyd roller or mech solid roller???
My ideas are to go with a roller cam/lifters, go from a 2800 stall to around a 3400. (when I ordered the 11" coan 2800 stall, I gave them the specs of my combo, and as for the weight of the car that they asked me about, I think I told them around 3200 or so and actual weight is 3550 w/driver, so I think the '2800' stall may be a miscalculation due to the incorrect weight of the car and I think I told them I'm going with a 3.73 but I ended up putting a 3.42 in it?????? but either way, I just drove a car with a more 'real' 3400 stall and was very noticable compared to mine, which I can live with more revs until the car gets going.
So, if I go with a roller cam and lifters, which one should I go with?
Again, I'm going to go with a 3400 or so converter.
As for gearing, I'm running a 3.42 and plan on keeping it that way, I take some nice cruised with the car and 3.42 seems to be perfect, and 3.73 would rev to high for too long of a period of time.
I'm also thinking of going with a Holley Street HP 750 instead of the Street Avenger 670, good idea or not?
While I have everything apart, I'm going to go with a different head gasket to bump the compression from 10:1 to a bit higher, somewhere around 10.5-11, still run on pump gas 93octane.
Well, any advice on what to do here????
 
#20 ·
Before you run it anymore go here and get a free oil sample kit:
http://www.blackstone-labs.com/free-test-kits.php

Send it off and put in the notes what oil and engine combo you were running and what happened. If it comes back with high iron then it might've started to eat the cam up. It could just be an issue with the locks though. Since you're pulling the engine anyway you'll eventually see if that's it or not but the analysis will at least let you know if your planned upgrade is just going to be the cam change or if you actually need to get the engine cleaned out in addition.

With RPM's your lifter load goes higher an higher due to the dynamics of the valvetrain. At 4000 RPM you're getting lifter load possibly up to as much as twice your static spring load. So, an extended run at that speed is rough on the valvetrain.

You may be hitting the ceiling on the 670 soon.

I think I'd deck the block before playing with head gasket thickness on an aluminum head iron block combo.
 
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