Thread: How do i get 400 hp from a 355?

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i have a small block 355 somewhat built and i want to know what else i need to do to reach 400 hp. I have a edelbrock performer rpm intake and 750 cfm carb. i shaved the stock heads .030 and already have roller rockers of course its been bored .30 over. i have heddman headers and glasspacks

that's not enough info...
What are the cam specs?
What style are your pistons? (Cast, Forged, Hypereutetic)
Are your pistons dished, domed, or flat?
What compression ratio are you at?
Are you against power adders? (nitrous, ect)

Just to tell you up front, most of your power is going to come from your cam, heads, and compression ratio.

well my pistons are dished, cast and i have a comp cam but not sure about the specs on that its big i know that but not sure about the specs and i dont know about the comp ratio and id like to see how much i can get without adders

It's gonna be difficult to know how to get to where you want to go without knowing where you're starting from. Putting a high performance motor together takes a plan wherein you choose parts that will compliment each other toward a goal. If you don't know what parts you have now, I don't know how to advise you to proceed

ok ill call my friend and find the specs on that cam and try to get a comp ratio figured out

If you are running headers and a 750 Holley, I would guess that you are not using the ECM anymore. If that is the case, and you want to make 400 flywheel horsepower, you can do that easily. Making 400 horsepower at the wheels is a whole different story.

Assuming you meant 400 flywheel horsepower, and not knowing what your cam is, I will bite and offer some suggestions.

You said that you were running the stock heads, so your engine has about 9.1 to 1 compression. That is sufficient for the street.

Your heads are an unknown. In order to make good horsepower, you are going to need a set of heads other than stock smoggers. This is where you will make your power, so spend your money here. You could EBay or go to Summit. Sportsman II's by World Products or any of the AFR's are good heads. There are many, but those two are definitely good.

As for a cam, with the setup you have I would look at something similar to the Comp Cams CCA-12-212-2. It would work with your stock torque converter and has a good power range. If the specs of the cam that you have are similar, use it. Otherwise, replace it.

Your pistons are crap, but if you are on a budget and don't intend to add nitrous or race at the drag strip, they will work. If you have the money, a set of hypers for non-nitrous, or full forged for nitrous would be another wise place to spend money. If you are going to replace the pistons, I would seriously consider some flat-tops instead of the dished ones that you have. Don't try to run flat tops with the stock heads though. That would put your compression at a point where pump gas might not be sufficient.

Last but not least, your distributor was designed to allow the ECM to set the ignition advance curve, but you are not feeding the ECM. You will need to replace your distributor with one that uses vacuum advance and flyweights from an older model if you haven't already done that.

These suggestions are only educated guesses. If you could provide more information, we could help you better. I would also suggest that you go to amazon.com and buy David Vizard's book "How to build Max Performance Chevy Small Blocks on a Budget". It is a great source of information, and has 10 different engine combinations that they built and dyno'ed which put out as much or more horsepower as you are looking for.

I only agree partly with this last post.

Firstly, cast pistons are not crap. If they were such crap then the factory wouldn't use them and for dependabilty vs. performance, cast pistons are nothing to be ashamed of. I've seen stock motors go upwards of 300,000 miles and still running.

Second, there are some stock heads that perform very very well. For example the 461's are a fabulous head for a high compression small block. The 441's are pretty good for higher displacement engines. I'm using 441's on my 4.155 bore 377 cui ground pounder.

I also don't see where the distributor currently in use is shown.

Also, there's NOTHING wrong with running a flat top piston. They are made for higher compression that dished, but, when paired with the right chambered cylinder head, can run low enough compression that 90-93 octane gasoline would be sufficient.

I run a 4.155 bore with a 72 cc head and my compression is around 10:1 which is, btw, in range of pump gasoline.

But of course, it all depends on your budget. If you have a few grand, there's a lot of things you can do to make that 355 push 400hp. But if you only have 20 dollars and a coupon for a free slurpy at the local ez go, then your probably not going to get anywhere.

Power = Money, how much do you have?

I would say 10:1 compression, good heads, an intake tuned to make power to 6500 rpm, a 750 cfm carb, and a cam with an advertized duration around 280-290 degrees. It's all in the heads.

well i have plenty of money, and i dont have a stock converter or distributer , B&M 25-55 converter and msd ignition, my heads are also shaved .030 and my block is bored out .40, i plan to either port and polish my heads or get some aluminum edelbrock performer rpm heads for better performance and to just keep em cooler

with the money, and a plan 400 HP is easy.

Plenty of money !! Heres the easy way to get a guaranteed 400 HP.

Convert it to a 383

Bolt a Weiand ^&! bower Kit on top

400 HP easy and you can feel the pull at low revs to high midrange

Originally Posted by southerner

Plenty of money !! Heres the easy way to get a guaranteed 400 HP.

Convert it to a 383

Bolt a Weiand ^&! bower Kit on top

400 HP easy and you can feel the pull at low revs to high midrange

and a very thick oil pan to keep the rod in

Originally Posted by pat mccarthy

and a very thick oil pan to keep the rod in

Oh well I said the easy way, may not be the cheapest way

Originally Posted by southerner

Oh well I said the easy way, may not be the cheapest way

yes a 383 with a good set of heads and some good pistons an good crank and 6 ich rods and then a blower or a blower on a maypop with a mild cam the blower is the way or NOs but the bottle needs to be filled if the belt on hang on

Originally Posted by #1firebird

well i have plenty of money, and i dont have a stock converter or distributer , B&M 25-55 converter and msd ignition, my heads are also shaved .030 and my block is bored out .40, i plan to either port and polish my heads or get some aluminum edelbrock performer rpm heads for better performance and to just keep em cooler

Plenty money = Start from scratch

1. Rotating Assembly
356-B13005L+040 SB-Chevy 383ci Street & Strip Rotating Assembly, .040'' Overbore
Bore x Stroke: 4.040'' x 3.750''
Rod Length: 5.700''
Pistons: Keith Black -7cc Flat Top
Comp Ratio: 11.7:1 w/58cc, 10.9:1 w/64cc, 9.6:1 w/76cc
1-piece Rear Main Seal

$945.99

2. Heads
158-1011004 SB-Chevy Race-Rite 180 23° Cylinder Heads
180cc Intake Ports
67cc Combustion Chambers
2.020'' Int/1.600'' Exh Valves
1.470'' Valve Springs
.525'' Max Lift
Straight Plug
Assembled, Sold in Pairs

$1,299.99

3. Cam
CompCams 249-CL12-250-3 Xtreme Energy XE284H Hydraulic Flat Tappet Camshaft & Lifter Kit
Lift: .507''/.510''
Duration: 284°/296°
RPM Range: 2300-6500
$175.99

4. Misc.
Head Gasket: 375-1094
Embossed Shim
Bore: 4.100''
Compressed Thickness: .015''
$19.99


Pushrods: Comp Cams Magnum Pushrods

Magnum Pushrods are the perfect complement to your Hot Street, Bracket, Oval Track, or any other high performance engine. Magnum Pushrods™ are one-piece .080”wall chromemoly steel. These pushrods are an affordable alternative for engines needing a pushrod to stand up to higher spring pressures and the associated stresses of a high performance engine. All Magnum Pushrods™ are Heat Treated to be compatible with guide plates.

Intake: 350-7501 SB-Chevy 262-400
Performer RPM Air-Gap
$203.99


Carb: 510-O-80770 770cfm Street Avenger Carb
Electric choke
400 to 500 HP
$364.99


NOTES:
You will have 10.5:1 Static Compression Ratio and 8.25:1 Dynamic Compression Ratio.
The embossed shim gasket will work with a stock deck height of 9.025 with the piston .025" in the hole to end with a .040" quench.
You will need to check pushrod geometry and get the correct length pushrods accordingly.
Use 1.5 rockers.

Just dynoed exact engine and made 438ft/lbs torque@4400 and 449hp @5900. It has a very flat torque curve and doesn't dip in hp until after 6300 rpm. A 1" open spacer added 12hp to the top but cost just as much or more torque in the lower rpm.