Thread: Chevy SB Advice please

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I have a 1989 chevy truck, looking to put a small block 400 in it

does anyone have an engine setup that isnt to wild, I will be driving this rig daily, I want some pep but not so much that I am working on it every week...

looking for something with alot more power than stock but not to crazy as far as horses and fuel consumption etc.

thanks for your time and input

I am new to all this, I didnt even know there was a law like that... there is a 5.7 in there at the moment 350 block 67k miles on it...

I could take that block and stroke it I guess add some parts etc.

what do you think?

ok, if I keep the block I have what would you suggest I purchase to beef the motor up, stroke it, new crankshaft pistons??

any input wiould be great

The federal tampering prohibition is contained in section 203(a)(3) of the Clean Air Act (Act), 42 U.S.C. 7522(a)(3).

Ain't it a beeeyotch?

Hey Swate, stroking a 350 to a 383 is a mild modification. If you can handle paying a little more at the pumps, maybe up the compression and change the cam. It won't be a tire ripper, but you will feel it in the seat of your pants. I love the "seat of the pants" meter.

Well, I've never seen the FBI or CIA out enforcing the Clean Air Act. Emissions enforcement has been left to the individual states to police. So it depends. Do they do emissions testing in Houston? And if so, are they just worried about the sniffer or do they mandate that it must passa visual. Michigan never worried about the visual as long as it passed the sniffer.

As for an engine, how much were you going to invest in your 400? The ZZ4 GM crate motor can be had for around $3500 at your local GM dealer, can be made smog legal, and comes with a 2/24 warranty. Did I mention the 355 HP? Just something to think about.

Hi Swate!
If you ask me, you can get more Power AND better mileage out of an engine with a few not very costly modifications. Get an Edelbrock Performer 600cfm carb with a Performer Intake, Open Air Filter and a set of good Headers. That wil give you about 20 or 30 more HP over stock, and a good lot of low end torque becasue the engine can breath better. And the mileage goes down because the Ede makes a much better mixture than the Rochester Quadrashit thingies. Might cost you about 500 bucks all together, won't fetch you a tire-burner, but you will defintely notice a difference in performance. I did those mods to the 350 Stock engine in my G20, runs far better now and uses less (I have other problems). What's most important is to set everything nicely. Valves ought to be adjusted well (NOT with the engine running, do the real thing with hand-turning and so on, gets you a lot exacter, and the more equal your cylinders are set the better the engine will run), and the carb will need the right set of needles, rods, springs etc. for your vehicle and driving habits. If you want real power, the next step from there is a new cam, but from now on your mileage will go down.

IMHO the sequence for tuning is (please anybody correct me if I'm mistaken):
-Airfilter
-Carb
-Intake
-Headers (and high flow exhaust systems)
-Cam
-Heads
-other block stuff (boring over, pistons, crank etc...)

If you want to build an engine to your specific needs get as many different opinions as you can, think of your pros and cons and try to build your engine with harmony. Just putting in a new cam will make your Power go up, but it will also radically increase you consumption. Add a few other things to match the cam and you'll get good power, better running conditions and your fuel consumption will stay within the green. That's my opinion.

I say go ahead and put the 400 in there. Just use heads with centerbolt valve covers and keep a stock looking injection system on the motor. There will be no way for a smog shop to tell the difference between the 350 and the 400, unless the guy knows the older block had a driver side dip stick and a 2 piece rear main. If you're really worried about it, grind the casting numbers off of everything and copy the numbers from the old block onto the new one using JB weld. Paint over them and nobody will know the difference.

<- disagrees with max about MPG of a Q-jet. A properly tuned Q-jet sings, & will outperform that Edelbrock & easily out MPG it as long as you dont have your foot into it all the time. John

What's the story on replacing the 1.5 ratio rockers with 1.6 ratio rockers? There seems to be a range of different rockers, but Speedway offers roller tipped 1.6 rockers for about $80. Is it necessary to add guide plates with these? I note the pushrod holes in my 350 ('76) are pretty small and sort of square. Can you just replace the rockers without guideplates and thereby gain H.P. and torque? The roller tips are supposed to reduce friction significantly as well. If so, that is an easy and inexpensive way to improve the power of the engine. I already have stronger chrome-moly pushrods but maybe they are necessary when changing the rockers?

Don Shillady
Retired Scientist/teen rodder

Don,

1.6 Rockers will give your cam 6.7% more valve lift and slightly more duration. In effect, it gives you a bigger cam, which should increase both horsepower and torque. If you use them, you need to make sure that they will not cause your valves to hit the piston. I changed the rockers on my Fast Burn 385 to full roller 1.6's (not just roller tips), and the factory says it's no problem. You need to do some checking for your engine, but unless you have a very high compression engine, there's usually no interference.

I used the same trick on my GTO. Changed from 1.5 to 1.65, and it made a noticible difference.

The roller tip will reduce friction quite a bit; however, in my opinion, the HP gain is rather small. The real benefit is in extended valve train life.

Does your engine have self-aligning rockers? If it does, and you change to the Speedway roller-tips, you will need guide plates - at least I'm pretty sure you will. There seems to be nothing on the roller end that will capture the valve stem and keep it aligned. To make sure, call Speedway's tech line and ask them.

Good pushrods are allways a benefit.

Add to the list Madmax sent a set of 1.6 rockers. This morning I called the tech guy at Speedway and he said for my '76 350 there is no need for a guide plate, just replace the stock 1.5 lifters with the Speedway roller-tipped rockers and the small pushrod holes in the head will keep the roller tips centered on the end of the valve. I'm not sure when the heads changed but maybe it was when the split two-piece rear seal went to one-piece. Evidently the earlier heads on SBC had rather small holes for the pushrods and on my 882 heads they are sort of squarish with only a little clearance. I suppose there is a certain amount of wear on the sides of the pushrods due to this tight fit, but there should be plenty of oil there. Thus I ordered a set for $90 which came to $98 when shipped from Lincoln Neb. to central Va. The "later" heads with larger oval holes for the pushrods will need self-guiding rockers, but you will have to check the year of your heads and check with the mfgr. about self-guiding; apparently the "earlier" heads permit a simple replacement. One factor that is important to me besides making the lift and duration of the cam slightly bigger is that the rollers reduce the rubbing friction on the bottom of the lifters so that on another thread it was pointed out that the oil temperature may be as much as 20 degrees lower (reference: Tech1?) and this should lead to slightly lower running temperature. Of course there are also larger lift rockers for Ford engines and BBC as well as SBC.

Don Shillady
Retired Scientist/teen rodder