Hot Rod Forum banner

horsepower guesses?

71K views 212 replies 14 participants last post by  abigassbowtie 
#1 ·
I am new to this site I am building a sbc 409 (.040 over 400) Im kinda new to the engine building I would love to put it on a dyno but just cant justify spending 400 on somebody else tuning my motor and knowing how much horsepower it makes anyway this is what I got and please bare with me I dont know all my part numbers

holley street avenger (670?)
ported edelbrock performer rpm heads stock valves 64cc chambers
holley strip dominator intake
speed pro forged pistons -4cc dish = 11-1 cr
solid roller comp xr 292
in a 509 400 block
stock polished and shot peened rods (5.7)
stock crank

anyway what do you think for hp and torque I know some of you guys are real good at this and I know everyone thinks that theyr motor makes way more than it does so dont hold back
 
#152 ·
abigassbowtie said:
I am new to this site I am building a sbc 409 (.040 over 400) Im kinda new to the engine building I would love to put it on a dyno but just cant justify spending 400 on somebody else tuning my motor and knowing how much horsepower it makes anyway this is what I got and please bare with me I dont know all my part numbers

holley street avenger (670?)
ported edelbrock performer rpm heads stock valves 64cc chambers
holley strip dominator intake
speed pro forged pistons -4cc dish = 11-1 cr
solid roller comp xr 292
in a 509 400 block
stock polished and shot peened rods (5.7)
stock crank

anyway what do you think for hp and torque I know some of you guys are real good at this and I know everyone thinks that theyr motor makes way more than it does so dont hold back
To answer your original question, it really depends on alot of things, what are your piston rated as far as compression? What kind of exhaust will be on it? What kind of lift does your cam actually have? How good of a port job was done on your heads?

I think the easiest thing for you to do is download a desktop dyno and enter in what you got as accurately as you can and you can get a good ball park idea from that. I torrented one myself and had it installed in about 5 min. Useful tool to have.
 
#153 · (Edited)
well i havent got the dipstick out yet cause im impatient but i did get my new tires on (mickey thompson drag radials in a 315-60-15) and i couldnt wait to drive it to see what the tires were like and HOLY hell they hook up amazing I had no idea what kind of difference they would make and they by far surpassed my expectations.

I cant do a full throttle launch with out spinning but if i launch around 2500 and stab it soon after it hooks and hauls ***. by far the fastest its ran and the fastest thing i have ever drove. I get the shakes for about a half hour after driving it

Now its time to get that pesky dipstick tube out
 
#156 ·
so this is off topic but i got a set of pistons given to me that are sterlings i believe. they are part number h635p but one of them is broken I dont have any use for these but they are useless without having all 8 of them. why can i not find another one for? sale did sealed power buy out sterling caues i found the part number but it was under that name ?
 
#159 ·
so my machinist said to just use a piece of brake hard line for the piece that goes into the block for the lower tube on the dipstick so my question is... if the hard line fits into the block the the dip stick isnt gonna fit in the hard line ! *** ? is my machinist an idiot?

i gotta get this p.o.s. fixed races open on the 8th
 
#160 ·
well i figured out the dip stick it slides down into the block a little ways I thought it sat flush so that problem is fixed!

now just for fun i put a vacuum gauge on my motor at the back of the carb where the power brake line hooks up and my gauge reads about 9 pounds of vacuum does that sound about right or do you think a might have a vacuum leak somewhere
 
#161 ·
Sounds about right for a cam of that size, its not going to make a ton of vacuum like a stock cam or street performance cam will.

The tube needed for the dipstick guide is a piece of 5/16" fuel/brake line, about 6-1/2" ling. Buy a 12" stick, cut it at 6-1/2"and keep the flare at one end, discard both nuts, and drop into the dipstick hole flared end up. Then install the upper dipstick tub as you normally would.
 
#162 ·
I ran into a guy that i have known for a few years and he has offered to help me get my truck tuned and ready for this weekend (first race of the year). Last night i went to his house and in less than 20 minutes it was running better than it has . Im going back over there today he said he has more stuff he wants to do. Im excited to have somebody that knows what they are doing helping me hands on.

Ill let ya know how it does this weekend

really would be cool to run low low 12.s
 
#165 · (Edited)
I've used the ProComp head before. I prefer to buy them bare and them buy the parts to assemble them from Competition Products so that I know exactly the quality of the components used. They will need a bit of hand port work, especially the exhaust side as those #'s are rather low.

I have bought other stuff from Skip without a problem, just never heads, so I don't know how good of parts he uses to assemble them, but he claims they are good pieces. At that price and from looking at the ad, you are going to have to pay a bit more for an valve and spring upgrade, as the valvetrain parts won't be correct for your solid roller cam.

This is the straight plug CNC'd chamber solid roller set up - http://cgi.ebay.com/ebaymotors/SBC-...r_Truck_Parts_Accessories&hash=item56425ff711 Price reflects the better parts needed for solid rollers.

You may be farther ahead $$$-wise to buy the bare castings, then valves from Competition Products, and move the springs/retainers that match your cam from your current Edelbrock heads to these new castings.

Or this set from White with .710" lift hydro roller springs and just swap springs/retainers with your Edelbrock set...leaves you able to sell the complete Edelbrocks or use them on something else - http://cgi.ebay.com/ebaymotors/SBC-...r_Truck_Parts_Accessories&hash=item4cf4e44d5e
 
#169 ·
The Pro Comp is much better on the intake, and a little worse on the exhaust, a situation easily fixed with about 2 hours time with a cartridge roll and a die grinder. Really basic, easy to do work on the exhaust port.

Once this is taken care of my sim program shows a 40+ hp increase over the Edelbrocks.

A change to 1.6 rockers shows a 15hp increase also, you really need more lift.

How Edelbrock keeps selling heads with such weak flow #'s in todays market, for the price they do, I am at a loss to understand. :confused: Their Performer RPM SBC head is barely any better than a stock GM L31 Vortec head.
 
#170 ·
I have a guy interested in my heads @ $900 wich is enough to buy assembled procomp 210s with cnc ported comb chambers and solid roller valve springs. do you think i should buy those heads bare and buy springs and valves seperate? if so could you advise me some part numbers on something pretty equal in value as to buying them complete ? and when i get the valves do i need to lap them in or do i need to have seats and guides put in? I dont know how bare they are gonna be i guess!

I would be kinda excited to do some port work I wouldnt mind doing some port work on the intake side if that would pick up as well
 
#171 · (Edited)
If you buy them bare they come fully machined with guides and valveseats installed and valvejob cut. Lapping would be used to confirm the valvejob is okay if you want.

If you buy them complete from White they should be ready to run, would just need disassembly for porting if you desire to. You can make a decent improvement blending the intake port with a cartridge roll also, 10-12cfm.

Buying bare and completing yourself will come out around the same $$$ as his complete price, I don't think there is a bunch to be saved there, because you would also need spring seats, retainers, seals, locks, studs.

An advantage to buying bare us that you could choose 2.055 or 2.08" valves and have your local machinist recut the intake seats for the bigger valve if you want to go bigger. Last set I did was with a 2.055" valve. If you do go this route, Competition Products is the best deal I have found for valvetrain parts.
 
#172 ·
I did a little checking at Competition Products, you can get a 2.02, 2.055, or 2.08" intake/1.6" exhaust valve roller cam head assembly kit that has valves, springs, 10° Chrome moly retainers, spring seat locators, forged locks and seals for $270(2.02/2.055") or $283(2.08"). Comes with Howards #98541 1.500" valvesprings, 150lbs@1.850", 175lbs@1.800", 450lbs@1.250", 500lbs@1.150", coil bind @1.060", max lift .750".

Kit is #852326(2.02"), #852356(2.055"), or #852386(2.08").

You would just need studs and guideplates to finish, at around $50 with ARP studs.
 
#173 ·
well I know im all over the place on this but a guy has offered to trade me his dart pro 1 230cc aluminum heads if i gave him 400 dollars so i put everything i own for sale haha to make 600$ so ill have money for gaskets he says his are complete all stock with 2.08 intake valves no port work or anything so im shooting to get these hopefully this weekend
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top