bighoss77

just wondering how well this setup would work... i love 400 small blocks, built a few of them. now i am wanting to build a pretty much stock 400 small block, maybe a small cam and run a whole vortec setup on it to put it in a '96-'98 chevy truck. what all am i going to need?

6789olds

the 400 small block uses a flat tapet cam . i would use a 350 roller cam block and use a stroker kit 383 for that build are you going fuel injection or carb ? fuel injection will top out at 425 hp at the crank . a 383 with a lt4 hot cam 1.6 rr long tube headers and mild head port with at correct tune will hit that 425 hp quick and maxing your fuel system if you are still wanting more gotta spray it .

bighoss77

just thinkng of a stock build in a stock truck... just to be different. no crazyness here. i dont want a 383, i want a 400. its not too often you see a full vortec 6.6L, was thinking big block tq/hp in a small block. mainly for fun/cool factor.

mitchellmade

iTrader: (13)

You can use aftermarket hydraulic roller small base circle to clear rods suggest atleast a 5.7 rod 6 would be best small port bowtie vortecs with 2" intake valves would be better for performance and reliability less prone to cracking for they are a thicker casting if your running stock intake you will be limited but if you can get your hands on a marine intake you can push it further. I did this setup for a customer for a tow truck it dynoed out over 500 ft lbs torque and maintained it from around 2000 rpm to 6500

bighoss77

yeah it just something ive always wanted to do... i just built a mild 406 and put it in a '77 k20. basically got the truck running and sold it so i didnt have a chance to enjoy it. im not looking for major hp/tq... i just found a guy local with a 400 short block that he says has been stored since '95 and came out of a running '76 van. its not really a deal or anything at $300, but i just had some thoughts in my head

Gadgetized

iTrader: (9)

I used to be a big fan of the 400's. Heck I still have 2 complete engines. Now that I have tinkered with an LS engine I will never do another older style small block again. They didn't cool well, and you really need a good head on them if you want them to perform. If you have your heart set on one of them, I was say a vortec head at the absolute minimum.

hog

You'll need to run a Vortec 305/350 L30/L31 front timing cover along with a 4x reluctor wheel that the crank position(CKP)senor will read. The plastic front timing cover holds the CKP sensor in the proper orientation so it can read the reluctor.

Rolller cam would be nice, but you would need to run a cam button to keep the cam's for and aft cam walk in check. This may not be ideal with the stock plastic timing cover.

Keeping the cam within reasin will allow the stock poppets to fuel the 400 properly. The poppets are rated at 23.1 pounds per hour(#/hr). There is a GM retrofit kit thatwas designed as a warranty fix campaign for California trucks/vans as Cali gas and the poppets werent compatible. The MPFI retrofit repoaces poppets with Multec 2 mini-injectors located at the end of the spiders legs. They flow EXACTLY teh same as teh poppets, but arent as prone top clogging as they actually use and electronic signal to open the pintle rather than relying on fuel pressure to actually open the poppet valves like the stock CSFI system does.
The marine intake will help out as it flows better due to the lack of intake restrictions like the FPR/poppets/fuel lines and thedifferent internal design of the marine intake compared to the L30/L31 truck intake.

Post #9 of this thread has pics of the GM MPFI/Multec2 retrofit setup next to thestock CSFI poppets. It also has side by side pics of theCSFI intake and the MPFI marine intake manifold.
https://www.performancetrucks.net/fo...ghlight=marine
The marine intake isnt the be all/end all. On my bone stock L31 engine, it made a noticeable/marked difference in low rpm torque and mid/upper rpm power. I can only guess that with more cubes or larger cam that the difference would increase even more. Basically any intake manifold that uses the 8 intake manifold bolt and raised Vortec runners is an improvement over the stock intake.

Vortec Stroker built up a home ported L31 head Vortec 383 in his 97 ecab 2wd. With the STOCK fuel syetem(STOCK poppets, FPR, pump etc) and the LT4 Hotcam kit (.525"/.525" lift with the LT4 style 1.6:1 full roller rockers, 218º/228º duration at 0.50" lift on a 112ºLSA roler cam) and LT headers and decent exhaust, he dynoed at 330rwhp with 381 lb/ft torque at the rear wheels through a 3000rpm stall Precision Industries "Vigilante" performance torque converter. PCM tuning was done by Ed Wright of Fastchips. Since the dyno he has added a V-Maxx intake manifold spacer which adds about 1" between the upper plenum andf lower manifold thus increasing plenum volume.
http://www.taylorvertex.com/Products/index.cgi/vmax
He went from 3.73's to 4.30's and uses a 390/70/17" M&H drag radial and has run a 13.6 at 100mph with a 1.8 second 60ft.

Basically what I'm saying is the stock poppets can fuel a mild 400 if PCM tuning is good. But the stock intake manifold IS a major bottleneck in regards to upper rpm flow.

Vortec heads have a 64 cc chamber volume, but quite often they measure in at 62-63cc, so be careful with the static compression and with cam selection for a decent dynamic compression ratio.

A nice injected Vortec 400 would be a tire fryer and would be a great all around truck engine.

Post back with any questions, a 400 would be nice, but I always thought an offset ground 3.875" crank and overbore to make a 396 SBC always had a nice ring to it.

peace
Hog

bighoss77

i think im gonna pass on this idea for now and focus on getting the rest of the parts for my vortech v2 kit

troytrucks

what was your ending result on the build.. because i am doing the same on a 98 tahoe right now but i can't get it to idle right and the brake pedal is fairly stiff when in gear...

ZO6Ted

Had a 406 with a comp 280 hydraulic with crap 882 smog heads, no headers and Turbo 400 in a '73 Vega. No traction but plenty of fun!