Hello, everybody I have some questions for you gear heads. I have a 355 sbc with double hump heads with roller rockers and hypereutectic flat pistons from speed pro with a Cam and Lifters, Hydraulic Flat Tappet, Advertised Duration 278/288, Lift .420/.442, with edelbrock Dual-plane Edelbrock Performer EPS intake manifold with edelbrock carb 600 with headers and double roller timing chain just trying to see how much compression do i have and what you think about hp i have 3:73 gears with a 350 turbo wit a shift kit and a stall with 2600
First, we need chamber volume and bore/stroke to accurately determine compression ratio. A 355 is usually 4.03" x 3.48". The heads and piston configuration have the necessary parameters to complete the equation.
"Advertised" duration is of little use today. We "compare" cams based on the "@.050" tappet lift". The LSA (lobe separation angle) and ICL (intake lobe centerline) are the other important pieces of cam info.
We're not there yet. Post the casting numbers off the heads and give us the piston part number so we can see if they are 1.560" or 1.540" and how many cc's are in the crown.
Won't work. To get to 9.25 on a 355 with 64cc heads would require a piston with 16cc dish, not a flat top with 4 valve reliefs (5cc eyebrows). You don't know what's in the motor, so I can be of no further help.
I will add that the 461 heads were 62cc's when originally cast nearly 50 years ago and had tiny little 160cc intake runners, so I wouldn't expect too much from them in terms of performance without doing some work to them. Ported and with larger valves, they will flow about the same as L31 heads. If you do actually have flat-top pistons with 4 valve reliefs and 461 heads, the motor will have ~10.5:1 static compression ratio and unless you took precautions, such as tightening up the squish, it will have a hard time running on pump gas without detonation.
I don't know if I'm using the right term but I have a 355sbc with camel hump heads with 1.60/1.50 I believe also a edlebrock performer-plus cam Duration at 050 inch Lift: 204 int./214 exh.with a set of flat pistons bored .30 over from speed pro with a 650 edkebrock carb and preformance intake whats my hp it cant be 200hp lol:nono:
We should pass a rule, that all internet dynomometers use a fudge factor of +25%.
To the OP: Vinnie gave you an educated guess of Rear Wheel HP. This is always going to be less than Flywheel HP and WAY less than Benchracing HP
Im guessing Vinnie thinks you'll make 275-300HP.
You need to realize that you have 60yr old heads, a 40yr old mass produced camshaft sold to Edelbrock, and we're still guessing at things like compression ratio and ports; timing curve and several other things that make a difference. Contrary to magazine hype, an edelbrock intake is not a magical bullet to gain XX-horsepower across the board. This is the same with ANY speed part. Its all part of an engineered system. Also, please know when they changed the way HP was calculated by the OEMs in the 70s, a lot of your big motors put out much more pedestrian numbers. Not to mention you have to deal with say 91 octane or there abouts for a street car today
My old 350 in my Corvette(the way I bought it) similar cam,modified Holley 650 double pumper with 850 base plate,remove able air bleeds,1 5/8 headrs,Holley intake, made 205 rear wheel horse power after dyno tuning,and 279 pounds torque. The engine was low mileage,multi spark ignition,standard transmission.You engine might make more power? If it does make more power,I doubt it makes a lot more.
It might make less?
Didn't mention machine work anywhere or did I miss it? No machine work, 9cc ish 4vr pistons, (speedpro shows only a 1.550 in hyper 4vr pistons) .025 in the hole, typical .041 head gasket.....app 9.3 comp, not so good quench of .066.
Small Carb, small heads, small cam, low comp, sounds like Vinnie's guess might be pretty darn close and you might be real dissapointed depending on what your expectations are.
The block was bore to become a 355 and the block was in the hot tank and hone as well also lg journals with new cam and main bearing so now the bore is .30 .20 .20 for cam bearing and main bearing and using roller rockers with camel heads and double timing chain with a performer cam edlebrock 2102 and edlebrock intake 2701 with a 600 or 650 carb with headers and intake n exhaust just got reseated n flat piston heads
The block was bore to become a 355 and the block was in the hot tank and hone as well also lg journals with new cam and main bearing so now the bore is .30 .20 .20 for cam bearing and main bearing and using roller rockers with camel heads and double timing chain with a performer cam edlebrock 2102 and edlebrock intake 2701 with a 600 or 650 carb with headers and intake n exhaust just got reseated n flat piston heads
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