wadedwyer

I'm hoping some of you can help me with the rebuild of a 400. I have a set of Vortec heads that I want to swap on the block but I know it's not as simple as that. This is a stock 509 block.

I know with the stock pistons and Vortec heads, the compression would be way to high. I'm planning on buying new dished pistons (22cc dome) which will get the compression lower with the Vortec heads. I will have the blocked bored 30 over.

I have very little engine building experience, so i'm trying to keep this as simple as possible... Vortec heads, vortec intake, new pistons, new cam (I know the Vortec has lift limits). I'm not looking for a high hp motor, just a strong running street engine. I don't have a huge budget, so i'm also trying to keep costs down.

I'm not sure of a few things. Do I need to upgrade the rods from 5.56 to 5.7 to allow for a piston with a larger cc dish? If i have to go with a 5.7 rod, is there anything else I will need to do? I was looking at these pistons... http://www.summitracing.com/parts/uem-kb168-030 They use a 5.7 rod. I'm not sure if there are any options like this for the 5.56 rod.

The car is an 80 with a 4spd.

Any advice is appreciated.

MrJlr

ttt

BKbroiler

Are you sure about that stock rod length? I don't know much about 400s but I know that 383s with the same 3.75 inch stroke can use the stock 5.7 inch 350 rod. In any case, try to use your stock rods and get pistons to match. Regarding your Vortec heads, you will hear alot of advice to use something bigger but you're trying to economize. Save money on the rods and have the valve stem bosses on the Vortecs cut down so you can run a higher lift cam. Put in a Comp XE268 or XE274 flat tappet cam. With headers, full duals and a good carb you will make real good power from 1,500 to 5,000 rpm.

nonracer

Using the 5.7 rod can cause clearance issues between the rod bolts and the cam lobe the stock rods have a shorter rod bolt to clear the cam. You can keep the stock rods since your building a basic street engine but if you want a 5.7 rod you can probably find a "stoker" rod reasonbly priced these have an offset to the big end to provide clearance or you may have to grind a little off the top of the inside rod bolt when using a stock type rod.I would just keep the stock rods I had a 500 hp 400 with stock crank and rods in a drag car I had no issues with rods although they had ARP bolts

63mako

http://www.alexsparts.com/valve-spri...rf-hyd-roller/
This will solve the issue with limited lift with no machining. This is the link for Hydraulic roller springs. Check spring specs to assure correct pressures for your cam. Kits are available for flat tappet as well. If you go with this gasket with your vortecs and listed piston your @ about 9.5 to 1 compression. http://www.summitracing.com/parts/cg...make/chevrolet
Drill the steam holes in the head in a street application. Vortecs are different. Here is some info.
http://www.chevelles.com/forums/arch...p/t-37235.html I would go with new 5.7 rods. By the time you recondition your stock rods and buy new rod bolts you can buy a new set of 5.7 stroker clearanced Scat rods.

nonracer

I agree 100%, this would be your best solution

wadedwyer

Is there a set of 5.7 rods that you recommend? Are there specific sets that don't cause clearance issues in these 400's?

Thanks for the info on the springs. I will pick up a set after i decide on a cam.

garygnu

its best to buy a rotating assembly ,check out competition products for a 400 crank /rod /piston combo.I feel the vortec heads would limit the power of your 400,consider some better heads.with some better flowing heads already set up with roller springs you can get a nice roller cam.

wadedwyer

I already have the vortec heads so I prefer to use them at this point. Buying a new rotating assembly is more than i'm wanting to do at this point.

hugie82

You're in a strange spot Wade because you're gonna spend a lot of money to make those heads work and you're gonna spend even more modifying your rotating assembly.
My advise, get a summit rebuild kit for the short block.

Sell your Vortec heads.

Apply the money to a nice set of aluminum heads with the correct chamber size, valve size and will accept a nice cam and manifold.

You will save and gain power at the same time. Also don't worry about the 5.65 stock rods that come in the 400 the longer rods barely make a difference in the horse power range you are operating in.The rotating assembly on a sbc 400 is more than capable to handle 450 HP

wadedwyer

Yeah, i do understand what you're saying. I'm not completely opposed to going a different direction. I would prefer to stick with the 5.56 rods as i realize they can handle more than what i'm wanting to build. Is it possible to get a larger cc dished piston (18-22cc) that will work with the 5.56 rod?

I was looking at these kits... http://www.ebay.com/itm/COMPLETE-SBC...-/350499577117 What do you guys think?

hugie82

Opps you got me on the rod size off the top of my head

It's been brought to my attention that these summit rebuild kits come with pistons that sit far below the standard deck height so heads like this might work out perfect!
I'm telling people now to build your short block first. Then you can get heads with different size chambers. For example; if your block is good and only a bore is needed with no need to mill the deck height. Your pistons may sit about .020 below the deck at TDC. If this is the case a 64cc chamber will give you around 10.5 to 1 compression. For which is a nice street motor with aluminum heads.

If you don't understand a term or anything, just ask! There's NO stupid question!!!

63mako

I think ProComp heads are junk. Better off with the vortecs.

wadedwyer

A rebuild kit like this.... http://www.summitracing.com/parts/fem-mhp138-300 comes with dished 12.5cc pistons that would work with stock 5.56 pistons. Would this kit work with a set of Vortec heads or would the compression still be too high? Compression calculator shows on the high end of 10:1.

Thanks for all of the help so far. I feel like i'm only getting more confused...

bluedawg

I agree, procomp heads are brought to you by communist China.