400 sbc build

[Jbug.jbone]

Thinking about putting a motor together for my wagon. Pretty dead set on a Chevy 400sbc. Car won’t ever see the track/strip. Just want something fun, and to daily. Motor will not be getting bored out, what kind of pistons and heads do you all recommend

 

[scoti]

Thinking about putting a motor together for my wagon. Pretty dead set on a Chevy 400sbc. Car won’t ever see the track/strip. Just want something fun, and to daily. Motor will not be getting bored out, what kind of pistons and heads do you all recommend

How do you know the motor "won't be getting bored out" already? Has that part of the build already been completed?

400ci on the street should be fun if done right. Spend your $$ on the best flowing heads you can get for the task.
Pick a mild cam for the rpm range (1,500-5,500 for the street) & then choose pistons that will get you decent compression to run it on cheap gas (87 octane) for that combo.

Factory 400 sbc's had like 22cc dished pistons & 76cc iron heads that didn't flow well. They were probably 8.5:1 motors @ best. A flat-top piston will put you around 10.1:1 so something in between (less piston dish/smaller head chamber). A mild 9.0 - 9.5:1 motor w/the right supporting parts (gears, stall if auto equipped, & exhaust) would be what I would target if starting from scratch.

 

[Jbug.jbone]

How do you know the motor "won't be getting bored out" already? Has that part of the build already been completed?

400ci on the street should be fun if done right. Spend your $$ on the best flowing heads you can get for the task.
Pick a mild cam for the rpm range (1,500-5,500 for the street) & then choose pistons that will get you decent compression to run it on cheap gas (87 octane) for that combo.

Factory 400 sbc's had like 22cc dished pistons & 76cc iron heads that didn't flow well. They were probably 8.5:1 motors @ best. A flat-top piston will put you around 10.1:1 so something in between (less piston dish/smaller head chamber). A mild 9.0 - 9.5:1 motor w/the right supporting parts (gears, stall if auto equipped, & exhaust) would be what I would target if starting from scratch.

My man! Thank you for the reaponse

How do you know the motor "won't be getting bored out" already? Has that part of the build already been completed?

400ci on the street should be fun if done right. Spend your $$ on the best flowing heads you can get for the task.
Pick a mild cam for the rpm range (1,500-5,500 for the street) & then choose pistons that will get you decent compression to run it on cheap gas (87 octane) for that combo.

Factory 400 sbc's had like 22cc dished pistons & 76cc iron heads that didn't flow well. They were probably 8.5:1 motors @ best. A flat-top piston will put you around 10.1:1 so something in between (less piston dish/smaller head chamber). A mild 9.0 - 9.5:1 motor w/the right supporting parts (gears, stall if auto equipped, & exhaust) would be what I would target if starting from scratch.

hey thanks for the detailed response. The only reason I say it’s not getting bored over. Is I just want a mild build for now. Plus the shops near me are backed up for months

 

[Texas82GP]

Make sure the heads are drilled for steam holes. 400 heads from the factory were drilled with them. If you buy new heads, they won't be. The 400, with its siamesed bores need the steam holes in the heads for street use. Otherwise you're likely to suffer overheating problems.

My car had a 400 in it when I bought it. Unfortunately, it was worn out and needed an overhaul. It had already been bored 0.030" over and the cylinders had a substantial ridge at the top so I moved on. Worse than all that, the heads it had on it hadn't been drilled for the steam holes. I had trouble with it running hot in the fall here in Houston, without running A/C. It wasn't a good setup.

Some good info here....

How To Build A 400ci SBC Torque Monster For $2,500!- Car Craft Magazine

We build a 400ci Small Block Chevy for $2500. How did we do it, read the full article for details and some great tips. Only at www.carcraft.com, the official website for Car Craft Magazine.

www.motortrend.com

 

[scoti]

My man! Thank you for the reaponse

hey thanks for the detailed response. The only reason I say it’s not getting bored over. Is I just want a mild build for now. Plus the shops near me are backed up for months

Make sure the heads are drilled for steam holes. 400 heads from the factory were drilled with them. If you buy new heads, they won't be. The 400, with its siamesed bores need the steam holes in the heads for street use. Otherwise you're likely to suffer overheating problems.

My car had a 400 in it when I bought it. Unfortunately, it was worn out and needed an overhaul. It had already been bored 0.030" over and the cylinders had a substantial ridge at the top so I moved on. Worse than all that, the heads it had on it hadn't been drilled for the steam holes. I had trouble with it running hot in the fall here in Houston, without running A/C. It wasn't a good setup.

Some good info here....

How To Build A 400ci SBC Torque Monster For $2,500!- Car Craft Magazine

We build a 400ci Small Block Chevy for $2500. How did we do it, read the full article for details and some great tips. Only at www.carcraft.com, the official website for Car Craft Magazine.

www.motortrend.com

Whether it needs to be bored or not is dependent on the condition of the cylinders. It's not something you choose. If the cylinders aren't in good shape, they can't seal in the compression to make it run correctly. Low cylinder pressure = weak & inefficient power pump.

400's are known to generate heat in correctly functioning form. While they'll run w/o drilling the heads for the steam passages, they definitely won't run cool. They'll also be a PITA.

 

[Ernest]

Ahh yes, the 400cid street bruiser engine.... plenty of torque on tap, so it will suit your wagon well.

Heres a compression ratio calculator from SUMMIT to help you along on making sure that engine has plenty of street manners to your liking - https://www.summitracing.com/newsandevents/calcsandtools/compression-calculator

Example...

 

[64nailhead]

Hydraulic roller 232/236, Profiler 210 heads, 9.5-10:1 compression with a 6" rod .... 450 crank HP with street manners. Plenty of chop but will run decent with a 2500 stall converter. Turbo 400 of course or 4L80.

 

[scoti]

Cam timing will play a big part of working compression in a budget 400 'street' package. Mild cams w/less overlap don't bleed low rpm cylinder pressure so it gets trickier from the 87octane perspective.

 

[1320John$$$]

I can get you started with a deal on a std bore piston NEW
Wiseco K051AS 6” rod 4.125 bore 1.120 pin
10cc dome Pins and locks
400$ you pay to ship
This is a750$ new when I bought them piston

 

[scoti]

I can get you started with a deal on a std bore piston NEW
Wiseco K051AS 6” rod 4.125 bore 1.120 pin
10cc dome Pins and locks
400$ you pay to ship
This is a750$ new when I bought them piston

Seems a bit much for a street ("no track/strip") combo. How much will the 6" rods set him back?