Projects 400 Small Block Chevy Engine!

lol

 

cam is 5 degrees shorter on the intake side, and (to be fair, I didnt go into this much detail) because the AFR's are better on the exhaust side then my current heads, I have gone to a single pattern, so it is also 9 degrees less exhaust duration than the old cam, so I have reduced the tail of the overlap triangle a bunch. I am losing a little idle quality with the narrower lsa, but if you graph the two cams out, and lay the overlap triangles over each other, the new overlap triangle is slightly taller, but the intake opening is later, and the exhaust closing is earlier. The total area under the overlap triangle is slightly less on the new cam, so the idle quality should be slightly better.

 

One other thing no-one has mentioned that you really need to be aware of with a 400, especially if you end up putting 5.7 rods in it, you need to be aware that with the 3.75 stroke, its common for the rods on 1&2 and 5&6 to hit the cam, so you need to order your cam with a small base circle. Whoever does the cam will know what you need if you tell them you are building a 400, but as a general rule, you are looking for a cam ground on a .900 base circle. you just need to tell them you need a "small base circle" cam, they will walk you through it. Some of them will even list them in the catalog. Go to someone like Bullet. I am not gonna comment on a cam recommendation on the open forum. I suggest you read Vizards book and do what he tells you, then I dont have to start a big controversy on here.

 

I will! Went to check the engine out today, found out it was the 511 model. from a 70's caprice I think. So it is the 4 bolt main. Should I be worried about that or not at all? I will read Vizard's book Tuesday probably. Exam week is coming up this week.....

 

For short duration WOT bursts like street or weekend drag use, I wouldn't worry too much about block integrity unless you cross the 550hp threshold.

 

I'll be producing 500-600. Somewhere in that range

 

Well um, then I need to revise my earlier cylinder head recommendation, you should be looking at 220-235 heads. Seriously. those and a Super Victor, 1000-1100 cfm 4150, 260ish @ 050, .650ish lift roller, 11.5/1 compression and 1 7/8 headers will get you in that range, if you tune it well, you can expect 1000ish rpm idle with about 8" of vacuum, and you can probably live with it on the street, as a weekend car. I have built motors like that, and invisible kid can tell you what to expect as well. I uh, think you just may be being a little optimistic... nothing wrong with that, but...
Seriously, for a first-timer, I think you will find that building a streetable 600hp 400 first time out is just a tad optimistic.
450 to possibly 500 is probably more realistic, and that upper number is really stretching it. This will be more like the motor in my truck, 245-250ish solid cam, 11/1, perf. rpm, 750 dp, idles about 850 in gear, about 11" of idle vacuum, takes a good five minutes of throttle blipping and at least one stall on a cold morning to get to where it will drive away without stumbling.

 

Ok. I love all the feed back everyone is giving me! Can we start to focus not just on the build, but the SBC 400 in general. Talk about core shift, what makes these specific engines torque heavy, why they are being used for racing engines even though they weren't originally thought to be like that, etc... I've got a lot of stuff to learn, I would love to learn about that stuff as well!

 

Nathaniel, sounds like you've stepped up the build plan quite a bit. 550-600 hp. Falcongeorge is spot on in the post above. Getting a stick car to live -reliably- in that range will take some trial and error (parts scattering) or some advice from someone who's been there.
What's the status of the 400 you purchased? Have you torn it down yet, got any pics.

 

First time I saw it was Saturday. I found out it is a 511 4-bolt main, so now that I know that it's a 4 bolt, I might want to lower it down to around 400 Ish. I think that is more that enough now that I am imagining it

 

Ive got the book by Bill Jenkins. On page 11 it tells about installing spacer sleeves and using the early small journal 327 steel cranks. Small bearing reduces bearing speed. My advice Build the 400 for RPM,s

 

Here's bearing spacers to use a 350 crank in a 400 block for a 377, that Old Wolf is discussing. They could also be used with large journal 327 crank for even shorter stroke. I haven't seen 400 spacers down to small journal 327.
http://www.jegs.com/p/JEGS-Performance-Products/JEGS-Main-Bearing-Spacers/750922/10002/-1

My personal preference is to build as many cubic inches as possible. 8-10,000 rpm is really hard on stuff, but man does it sound amazing.

 

I had two back in the late 80's. They came from a friend who raced circle track at Lakeport Speedway. One had alum heads and the other 462's as I recall. Put the iron head version in a 56 Chevy sedan with 4:11's and a high stall turbo 350-it had a Schneider spec track cam-unknown specs. It was very very strong. The alum head version I changed the cam to a milder one(Crane split duration) and put it in a 66 Nova SS with a 2500 stall turbo 350-mid 3 gears I think. It ran also very hard. Had to put a single plane intake on it to kill the bottom end a little. Wife ran em both at Sears Pt. Never wound em over 5800-guess HP was maybe 375?but lots of torque. Both cars ran low 13's with less than optimal traction. These were street cars and did not heat up. Motors were done by a circle track engine builder from Nor Cal-wish I still had one of these.

 

Wow! So one of the better projects you've done? Sounds like a fun car! What would you have changed if you could?? Thank you for the story!

 

Falcon. Our 400 Dart uses a 3.480" crank and by the racing rules require iron heads. At 374" the EQ 350 H heads work fine and started at 186cc on the intakes. Juan Mendoza did his magic and they flow 262cfm @ .600 which is about max using an iron cam also by the rules. Made great power 6400 and a torque line perfect for a 1/2 mile dirt track.

 

Thats great, and I actually have a flow bench and port heads myself. However, I would advise the op to buy the set of heads he needs in the first place, rather than buy some that are too small, and then pay some guy like me $2000-$2500 to make them work on his combination.

I have built quite a few 377's especially when I was younger, it wouldn't be my choice for a first-time builder. KISS.

 

Ive never done it. According to the Bill Jenkins book To install a small journal crank in a 400 block you use 400 main bearings and alighn bore them to accept the small journal main bearings. you gotta trim the thrust face from the rear main and stake the altered 400 bearings with a roll pin.