400 SBC Build - Tight Budget

Hey all!

My kids talked me into keeping my '84 "old school", and passing on the trendy LS swap. Although I'm looking forward to the build, it will be the my first "total rebuild". I fully intend to tap this great communities knowledge to minimize mistakes. I thank you all in advance.

BUDGET: 4 - 5k

ENGINE:

400 SBC (Pistons stamped .030, so assuming 406 ci)
509 Casting, 2 - Bolt Main

Cylinders looks pretty good, hope to get by with a hone. Plan to start with a hot tank and inspection before moving forward.

GOAL / USE:

450 - 500 hp (Bias towards regular pump gas and drivability)
Weekend cruiser / Show truck (eventually)

I need the 4 - 5k to cover the following: (is this even possible)

- Any machine / mill work required
- New rotating assembly (maybe w/ prebalanced damper / flywheel?)
- Assembled / Drilled (cooling) Aluminum heads

Any insight to making a good match with pistons / heads / CAM welcome - I realize it's just math...LOL, but at the moment seems like magic.

You're going to get a zillion opinions on this. I will give you a couple non-specific suggestions.

Do not go crazy on cam choice. Have seen way too many times people over cam an engine and regret it.

If within the budget buy a good quality hyd roller lifter cam and roller rockers. Contact the manufacturer directly for advice. Do not call a general retailer online customer service line.

Roller chain is another way to reduce internal friction. Get a single roller chain, not double roller.

Use hypereutectic pistons. Forged are stronger but require more skirt clearance.

2 bolt 400 blocks do not require 4 bolt conversion, they are plenty strong for average HP.

Keep the compression no higher than 9.5 for the street.

There are many aftermarket head manufacturers. I used Trick Flow on a 383. They were perfect in every way.

The local machine shops have said Scat products are excellent quality. Just looked at the cost of a rotating assembly it will bust your budget.

Have fun with the project.

If everything mic's out, you can save all the rotating assembly expenses. We rebuilt a 350 in '84-'85. It came out of a 76 K10, everything mic'd out within spec, so we cut the ridges, hot tanked it, honed all the bores, reused the crank, rods, pistons, cam, lifters, and re-ringed the pistons, new oil pump, new bearings, assembled it and it ran great. I daily drove that engine first in my '56 Chevy 210 from '86 to '91, and then in my '65 C20 until '98 when I got a crate engine for it. In '97 I asked Pop if he would do a valve job, he agreed. I calculated it had 194k on it by then, mostly highway miles, and none of them easy miles, I ran the piss out of that engine. When I pulled off heads there was no ridge this time around. When Pop got done with the valve job that engine ran even better. It was scheduled to go back in the '56, but life got in the way and I had to sell the engine and the '56. I miss that car with that engine in it.

So maybe just rod and crank bearings while they are out, run a stock low end and put the money into a really nice set of heads? I think I may need new lifters / CAM I knocked the tray of organized lifters off the bench, no way they are going back where they came from..lol

Right now the largest unknown is the machine shop costs. I have no clue what these costs are going to run me.

Do your own research on ,cylinder heads,spark knock,MBT (maximum
brake torgue/minimum base timing), compression and quench.these all 5 work hand in hand to make the most power on the least fuel with good drivability on pump gas.

This is an excellent read.Long but very informative.

GO-N-BRK_84 said:

So maybe just rod and crank bearings while they are out, run a stock low end and put the money into a really nice set of heads? I think I may need new lifters / CAM I knocked the tray of organized lifters off the bench, no way they are going back where they came from..lol

Right now the largest unknown is the machine shop costs. I have no clue what these costs are going to run me.

Click to expand...

If it's just a clean-up with a hone/bore it shouldn't break the bank, but expect it to be higher nowadays because of stupid inflation. I cringe to find out what my 292 head and block are going to cost me once he gets done with them.

450 to 500 streetable horsepower, on pump gas might be a hard thing to accomplish on a SBC, but still better than the LS swap. Do as much as you can yourself, with what you already have.

Start a spreadsheet to keep up with numbers your getting so you can keep track. If you have a computer, but don't have windows excel, just download open office......it's free.

The spreadsheet will be an easy way to keep your mind wrapped around the costs easily.

I agree with @fast 99 . Torque is more important than HP in a pickup, so don't get wild with the cam choice. A 400 has great potential to make very good power with a RV type cam. A good set of heads will be the best bang for your buck.

GO-N-BRK_84 said:

So maybe just rod and crank bearings while they are out, run a stock low end and put the money into a really nice set of heads? I think I may need new lifters / CAM I knocked the tray of organized lifters off the bench, no way they are going back where they came from..lol

Right now the largest unknown is the machine shop costs. I have no clue what these costs are going to run me.

Click to expand...

I got a 350 rebuilt about a year or two ago down here in Salem. It was ~$550 for clean/inspect, bore/hone .030" and match new pistons, install new cam bearings and freeze plugs, take .020" off the deck for better deck height/quench/compression ratio. On top of that it was about $1500 for all new stock rebuild parts including a redone set of stock heads and a summit flat tappet cam kit. It would have been another ~$1000 for aluminum heads and another ~$600 to go with a roller cam setup.

A good combo for your setup that would stay in budget would be a set of AFR enforcer heads from Skip White performance and a comp roller kit sk12-411-8 or sk12-412-8.

just make sure the heads have steam holes.

My 79 K5 has a 400 with 80k original miles on it.

It runs great, but needs mo' power!!!

Plan on throwing on a decent set of heads and a retro roller cam.

The stock heads have huge combustion chambers. A 64 cc head on mine should put the compression up to about 9.1 from what I've read.

Been seeing people destroking these lately. Dropping in a 327 or 350 crank, dropping displacement to around 354 c.i.
Making crazy power.

fast 99 said:

You're going to get a zillion opinions on this. I will give you a couple non-specific suggestions.

Do not go crazy on cam choice. Have seen way too many times people over cam an engine and regret it.

If within the budget buy a good quality hyd roller lifter cam and roller rockers. Contact the manufacturer directly for advice. Do not call a general retailer online customer service line.

Roller chain is another way to reduce internal friction. Get a single roller chain, not double roller.

Use hypereutectic pistons. Forged are stronger but require more skirt clearance.

2 bolt 400 blocks do not require 4 bolt conversion, they are plenty strong for average HP.

Keep the compression no higher than 9.5 for the street.

There are many aftermarket head manufacturers. I used Trick Flow on a 383. They were perfect in every way.

The local machine shops have said Scat products are excellent quality. Just looked at the cost of a rotating assembly it will bust your budget.

Have fun with the project.

Click to expand...

I'm am going to preface this by saying I am not an engine builder. But I've been mechanic for a long time, and the shop I currently manage does a fair bit of classic / older vehicle work.

What Brian said about cam choice. "Do not go crazy on cam choice. Have seen way too many times people over cam an engine and regret it."

I cannot tell you the number of classics we have had in the shop with so much cam that they were unpleasant to drive around town.
We have a regular customer with a 68' Camaro that is cam'd out. Yes, it a fun car when your hammering down, but driving around the city the shop is in sucks. I doesn't idle very well, the exhaust is awful and it's hard to control in traffic.

The customer does does not like this aspect of the car either.

"I need the 4 - 5k to cover the following: (is this even possible)"

NO

85K304SPD said:

450 to 500 streetable horsepower, on pump gas might be a hard thing to accomplish on a SBC, but still better than the LS swap. Do as much as you can yourself, with what you already have.

Click to expand...

Oh that can be done, my trucks 350 made 537 HP with production iron heads, but not for 5000.00

It's alarming what doing this cost today. If you want to try another rout, put a used 350 crank in. Thick bearings are available to fit a 350 crank in a 400. You will of course need pistons that have a 350-pin location and fit the larger 400 bore. Other option is re-ring the 400, buy aftermarket heads with intake, and a cam that fits the intended use. You might get it done for around $5000.

Before labor got so expensive, we used to re-ring engines all the time. They would last 40-60k.

If buying heads be careful choosing the right chamber size so it doesn't end up with too much compression. Swept volume of a 400 is quite a bit more than a 350.