I'm making just about 425hp, on a Vortec 350 block and bottom end (motor had 10,000 miles on it, so it didn't need any cylinder work or bearings, but I re-assembled with ARP fasteners, since it sees 6500rpm occasionally), Keith Black 10.8:1 pistons, cleaned up 70cc Performer RPM heads, upgraded springs, solid pushrods, scorpion 1.5 full rollers, Comp XR294HR cam, Performer RPM Air Gap intake, tweaked Holley 670 carb, full MSD ignition (box, coil, distributor), Hooker Super Comps, and a few other goodies. It's a little lazy down low, but pulls like a freight train from 3500 to 6000 rpm. It begins to nose over around 6300. Compression is just a hair under 11:1, and it runs just fine on 93 octane. It's been a really great motor for the street, and has decent manners in traffic. Do what you will with that info. Personally, I think expecting north of 400hp from that combo is pushing it. Upgrade the heads, and use a good cam in the 2500-6500 rpm range, and you'll get there. You're pretty limited on lift with the Vortec heads unless you do some machining, and you'd be better off with a 2.02/1.60 head anyway. But for a budget build, it should still run pretty well.
Sounds alot closer...you had me feelin like a slacker pretty bad on this one! My old small block with a 507 lift Isky stick with 265 @.050 10.5-1 Dart Iron Eagle heads and killer valvetrain stuff, a Victor and a 750 carb was good for an 11.90 timeslip. Dynoed just under 400 horse to the wheels... I always liked superstock stuff those guys know all the tricks! Race
does anyone know of a free dyno software so i can enter all the parts and specs and come up with the perfect engine?
Wont mention what my throw together 355 iron eagle runs then....lol. but will say, bullet cams make power .... Just out of curiousity, are your 60' in the low 1.60's? The @50 on you cam seems huge
i played around with desktop dyno 2003 and came up with this: -stock vortec with stock heads and stock 1.5 ratio rockers -Lt4 Hot cam -750cfm carb -dual plane high flow manifold -large tube headers with mufflers -flat top pistons and .015 gasket to up compression to 10.14:1 this combo would give me 375hp and 358 torque (at the flywheel) at 5500 rpm. with open large tuibe headers its 391hpand 374 torque. Does anyone have any other suggestions to bump up the hp. Dont wanna do any machine work and want to avoid changing heads. Any suggestions on a better cam?
Since you have DD, keep screwing around with roller cam profiles to up the torque curve a bit without raising powerband.
Having a really hard time finding full cam specs needed for DD for certain cams on summit racing. would anyone happen to know the valve event timing specs at 0.050" timing for this cam: Howards Cams 110245-14
it only gives me 2hp extra. Although by swapping the dual plane for a tunnel ram and using 1.6 rockers i can make 408hp with mufflers and 419 hp open headers. No luck so far finding vortec tunnel ram though
One of the car mags (I think CC) had a 355 build called "Danger Mouse" using vortec heads, RPM airgap, Comp Cam Extreme Energy, 1.6 rockers and a 750 carb that made around 409 hp. I built the exact combo but in a 383 using a one step larger cam and a 800 carb. We both used the vortec heads from S-D with the higher lift springs.
so it doesn't look like i am going to find a tunnel ram. But i can get 390hp if i use a single plane high flow intake instead of a dual plane. I also need to up the compression to 10.14:1. I can do that if i use +6cc flat top 4 valve relief pistons and 0.015 head gaskets. Do these pistons fit a stock vortec 350? What size rings i need? will these work? These pistons are less than a $100 bucks and will get my compression to 10.14. I was looking to get my compression to 11:1 that would allow me to make 408 hp but dont think i can do that for the price of these pistons that will get me 10.14. If anyone knows how i can get my compression to 11:1 for around 100 bucks let me know. I believe these will be the last questions i will ask. I think i have all the info i need. I will try and document the whole build when i gather the parts. thanks a ton
forget about those pistons i listed above. I really need to know if these will work with the stock vortec 350 and which rings i need? These willl get me a 10.81:1 compression. Which is perfect. They are dish with 4 valve reliefs
I lied too..recheched my cam card 250 duratiuon @ .050 108 lobe separation My 60' was 1.65 on average...never better than 1.63... The cam is an old isky Z50 solid grind,my favorite street cam. When I throw a small block together for a new kid I usually use a Z30 isky with stock diameter Kmotion springs. I usually make a newbie who wants to get into racing run a solid cam so they can learn the importance of valve adjustment. I like Isky stuff because he keeps conservative on the lift so you dont have to run crazy spring pressure and it keeps the valvetrain light.
Dont worry too much about advertised compression ratio numbers, get with a good machinist and have him check the piston depth in the hole..also dont be afraid to deck the heads to arrive at your final compression ratio. I spent alot of time hanging out at my local machine shop asking lots of questions before I built my first engine. There wern't forums full of desktop heroes back then! I would recomend a dual plane intake and if you don't want to have to warm the thing up forever I would run a gmpp intake rather than an airgap...I know it sounds crazy coming from a guy building a blown injected Hemi to drive on the street! Just my 2 cents....Race, Desktop Hero
thanks for the advice. Even if i dont go with these pistons. I just basically need to know if they work in a stock (non bored) vortec block. Just so i know. Why is it that a dual plane manifold will decrease over 25hp when compared to the single plane? PS whats the hemi going in?
As far as I know (not much aout later blocks) 350's a 350....4" bore is 4" bore. As far as the dual plane single plane debate.....I guess Ill give my .02...even if it is going to cause a fight, a single plane will make more peak horsepower than a dual plane...great on a dyno. A dual plane will make more broad curve, better on the street..Again this from a guy who never bought anything less than a Victor jr. or Team G sinleplane and ran 4.56 gears every day on the street. What are you doing with the car? How fast do you want it to go? Are you going to race it? how much do you want to spend? These are the questions you need to ask yourself, dont worry about horsepower numbers for now....Race
last year using a circle track crate 602 350/350 this motor comes with a dual plane intake,adding an adapter, two barrel holley one inch carb spacer timing at 32* retarded cam 4* 9.2 compression small tube header 1 5/8" x3"x18" made 380hp at 5500 flat torque from 3500 to 5500. on reg gas not high test. lost horse power with stepped headers recommended by GM may be because of the two brl carb. stock out of the crate with the stepped headers no spacer and no miles on motor made 355HP this is a non roller cam motor so your 400HP is very doable
You'd benefit from reading a couple of articles, one done by stock car racing magazine, google 500hp for $2500 and you'll find it. 2nd is popular hot roddings budget sledgehammer build, google and read
How do you plan on doing that? To have the rocker arms done (as in installed im guessing) the pushrods and lifters would be in as well... no cam will slide in at that point....
will the old muncie, saginaws, th350, th400s fit the vortec without modification? Thinking of getting an M20 4 speed from a 68 chevelle.
The single plane does a better job at delivering fuel and air evenly at higher RPM than a dual plane. However the single plane is not as efficient as the dual plane at delivering fuel at lower RPM. Look at the torque curve on the different Desktop Dyno builds. That curve will tell you how fun it will be to drive . The flatter & highest the earliest will be the most fun on the street . stop light to stop light seat mount tests should be a blast and higher MPG even if the peak HP is lower. A curve that's peaked, highest the latest is going to be the better/best for a all out max effort race car. This will decrease your low end torque so you don't over power the tires on launch. Let you stay on the curve during high rpm shifts and thru the lights. This curve would be aggravating on the street even if the peak HP is higher.
This is what I used for a guideline on my Vortec build. Click here: Vortec Small-Block Build - Popular Hot Rodding Magazine
Thanks for the advice. This car will be a weekend strip car so based on what you said I should probly go with a dual plane even though it will bring my hp down by over 25hp. I really wanted 400+ horses which I would get with a single plane. Anyhow, would carb spacers on the dual plane help bump up the horsepower or kind of work like a tunnel ram. According to DD a tunnel ram would bump me up to 420hp too bad they don't make them for vorects
Like I said I used it for a guideline. I have a flat tappet cam and a 650 cfm carb. Might be around 370 hp.
Well, figuring my 2.02/1.60 Edelbrock heads are at least as good as the Vortecs (should be better, especially considering the mild port work) in that article, my Air Gap intake is pretty much the same, my cam should make more peak power, and I have more compression...... I see some dyno tuning in my future..... Sorry to hijack.
would a home porting job on the stock 64cc heads up the compression and increase hp and torque without changing pistons? If so to what? If i do home port should i still change the pistons to the KB 1470-std? I have a dremel? and a box of accessories for it they are cheapies though? What do you guys recommend i use and how should i go about doiing it?
Vortec heads will draw you back on lift. For one, if you trying to gain lift then go with the Beehive springs comp cam offers. They are built for this intended purpose. Personally I would have the spring pockets machined to accept high lift and use high performance springs. High lift cams tend to drop valves if you dont have enough spring pressure. Also, you really need to look into screw in studs and guide plates. With a high lift/high pressure cams, those press in studs will pull right out causing engine failure. I am no expert on the performance side of things but have built a few gasoline and large diesel engines, but just recently built a 383 stroker. 450 hp 510 tq. I can attest that everything you do will lead to changing something else if you dont start with a solid game plan from the start. Compression ratio, stall converter, tire size, transmission, gear ratios and intake type will all dictate what kind of cam will give you most power. You can start with any of those listed above and then build around it.
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