I have an 85 rs with a 305 in it right now. Iam starting to get a build togehter on a 400. Im going .30 over and keeping stock heads. What is the best possible build. What intake? Carb Cfm? Cam Brand Specs? Roller/Flat tappet? Port/Polishing? Flat Top/Dish Top pistons? Comp Ratio? rocker Ratio? Rebuild kit? im just wanting a mean street motor that i can race every weekend This is my first build so any help and tips would be greatly appreciated!

 

You want to go flat top, edelbrock air gap Holley 4 barrel 750 and the bigest hr cam that you can run. Would not run stock heads. Get aluminum aftermarket.

 

Stock iron heads are terrible. If you do that it may want a dish piston not flat. If those are 76cc chamber heads a flat would give 10 to 1 comp and be sketchy on todays pump gas unless you have a big cam to bleed compression off. It would be a dog tho since stock iron 400 heads suck. Set of vortecs would be much better but still not large enough to really feed a 400 sbc. Vortecs also have smaller chambers so def need a dish piston to get comp in the 9's

 

Ok stock heads are gone...What are the Best Cost/Performance heads i can buy?

 

Whats your hp goal

 

Ive got a th350 so after its built with a monster kit im limited to 550hp 500tq but i would be happy with 450+

 

Budget aluminum heads id use dart shp 200's or jegs brand 210's. Jegs are profiler castings which are good stuff.
Replace springs with ones that match your cam requirements. Simple flat tappet hyd cam and those heads should do 450-500 hp. Something around 236-240's deg duration

 

World Products Sportsman II heads are about the best bang for the buck around. You can find a used set at a swap meet for about 500 bucks.

 

I think there are much better options than world sportsman 2's... With some work they do ok but out the box i never was impressed with any motor running them. Vortecs with a clean up and valve job would likely do better for less money. I just never was sold on world heads

 

New vortecs? Or pull em off a vortec and rebuild em ? I have a 700cfm edelbrock would that be enough carb for this motor?

 

Was thinking stock oem vortecs and rebuild them with a good valve job and maybe some mild bowl rework and new springs/guides cut down, decked. With those small heads, 700 cfm carb may be enough. 750-800 may be better but I'm not a carb guy. Bigger heads would be prefered. OEM Bowtie vortecs would be nice, they come in large and small ports which are both bigger/better than oem 90's truck stuff but if you spend the money on those new, you could also buy the bigger profiler 210's and make more power easier...

Its a tough call. Mild reworked vortecs with alittle port work may get you 450hp. 500 is a stretch without more serious work. Full port work + bigger valves.

I still think you would be better off with aluminum heads and a slight dish or flat top piston and a big cam and shoot for 500-550 hp Spend somewhat same money and get 50-100 hp more with your parts....

 

So aluminum vortecs? Valve job,guides seats,could i keep stock vortec springs? With the big cam and all?

 

No the only aluminum vortecs are edelbrock E-tecs which arent bad but for the price you can get better options. Would need new springs and stuff. I was refering to a non vortec aluminum head

 

Ok so back to best aluminum head cost/hp wise what would you recommend

 

Any head(s) you get non-400 you have to drill the heads for the steam hole marginal 400 cooling system. I would not attempt 500 hp on a stock rod length/stock 400 bottom end. And you do need to insure the pistons are final fitted when boring the block/honing using torque plates. These 400's don't have stable bores and move quite abit.You should be aware that your choices of heads is related to the type of pistons you chose where the c/r and cam dictates if the engine is acceptable for the unleaded pump gas. You need to plot out the build considering whether or not the heads are aluminum(which helps drop the compression ratio),the heads chamber volume,and consider what the static compression ratio is so you can choose a cam to provide what the dynamic compression ratio is at a acceptable level.

Cheap is just that,no freebies. So although some head companies might say they have a intake runner of certain size,whether or not they actually measure out to be that size leaves alot on the table. The runner sizes isn't as important as the cross section of a port and it's shape. So what is a consumer to do??. You buy a known brand name that has a long,long history of producing their product that has the funds to have done their research and development.

Just as Orr told you.To pick out a arbitrary number like 500 hp isn't a cheap affair and certainly to try to cheap out on heads is a bad idea where a bulk of the power is made.

While I think about this more,a hydro roller conversion kit alone will cost you from $300 to $500. As Orr told you,your going to need springs for your heads/cam. The basic lists of parts don't stop there. Rockers,push rods,etc. My point is I think alot of guys just consider the basic parts,but don't think to add all the other stuff to make it work where those at times can be another $100 here and 300 there,etc. It adds up quick. Larger cubic inch/hp engines vs smaller ones(Example a 400 vs a 350) costs more. Not thrilled with the idea of a stock block 500 hp 400. Have guys done it??. Sure. Build this??. Absolutely. Point being do so looking at the big picture costs. I just kills me after helping someone on line build a engine to find out they ran out of money and couldn't finish it parting it out.

 

No, they're about the worst heads available at any price. I wouldn't run them if you gave me a new pair for free. Back-to-back testing HAS PROVED that Vortecs can make the same peak HP with FAR more average HP, at less cost. ANY other 200 cc head will easily embarass these disastrous mistakes by a margin big enough you can't help but feel.

 

Already discussed. See post 7

As said above there are alot of small costs to consider that i am not outlining.

 

I agree with Orr89RocZ on the Vortec heads, not sure why you are hung up on Aluminum heads. Google "Roller Vortec dyno" and you will find probably 4-5 magazines that made 400+ horsepower with Vortec heads and a hydraulic roller or flat tappet camshaft on 350 and 383 ci motors.

 

Don't ever lose sight of those comic magazines main purpose is to promote the products in tests of it's advertisers. You got to know how to read between the lines on those articles. I have caught some of them playing dirty pool on those tests. As a example,when I worked in the Chevy engine plant's dyno rm,under the instruction of the engineers,I would and could manipulate results fairly easily.

It isn't as pure as rating a intake runner to a size like say 200cc. And there are some head manufactures that say there heads are a size and simply put they are not. But my point is what is truly more important is the port's shape and the cross section of the port. The only safe guard you have as a end user is to research the company's history you thinking about buying from and if they have the R & D department and equipment backed by programing. A example of a company like that is RHS. Their research is on going and continuous.


Now to deal with DCR's. The 8.5 DRC isn't just a guess figure. It accounts for all the variances in question. Open breathers also helps on a tightly seal engines.

 

I see your point. I copied the Chevy High Performance "440 horsepower Vortec" build which is essentially a 10:1 350 with Vortec heads and a comp xe274 and saw great results at the track. I cut a lot of corners and still had a car that was close to 11s at 112+. The magazines might inflate numbers, but I bet based on my mph I was close to 400 HP and that's not bad for a flat tappet. Now add a bigger carb, big hydraulic roller, etc he might actually see mid 400s.

 

Find a local cylinder head porter. They usually know someone who is upgrading and will make you a deal on a good set and they usually have flow numbers. I like brodix myself but I have seen guys run very well with fast burns.

 

I've got World sportsman's on my 355 and I'mhappy with them. nothing serious like the 400, but I'm hitting 320hp.

 

I purchased AFR 210 75CC and have great success with them.. Was worth the extra money to have them CNC too.