Thread: Need some advice

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I have a gm crate engine that was supposedly rated at 290 horse i bought 7 years ago, I am wanting to used the still virgin (never has been bored) block and beef it up to around 330 to 350 hp. I want to keep my compression ratio around 9 to 9.5 to 1. i dont wont to stroke it , maybe bore it 30 over and change my heads to a 64cc chamber 2.02/165 . Does anyone have any good ideas to get that hp, with a list of good parts i can buy either through jegs or summit ? Can anyone maybe run a desktop dyno for me so im sure to get that kind of hp? Im new to this fourm so i just wanted to say hello.. I have a 1977 chevy c10 2 wheel drive truck with a fresh 350 turbo transmission my tire size is R31.10.50/15 with true dual exhaust and a edelbrock thunder series 650 cfm .

well, you didn't mention cash flow? could be as easy as a rebore and a new tope end. they sell complete top end kits, heads, intake cam lifters etc. I know lunatti has one and I think holley does too, probly edelbrock has a package. they have the bucks to do the research.

Well cash flo is always the finial way to hp huh? ahhh as long as i can keep it under 2000.00 i guess . im not looking to race this truck . its going to be a daily driver . I will be towing a boat (runabout) but when i put my foot in it i want to feel it if you know what i mean . the old 290 hp is getting a little to weak for me now .

for cost sake, I would srtart with a intake/carb s/u, cam swap and headers and exhaust. talk to them at summit tell them what you want and they can help selct a grind for the cam. those mods alone may be enough to satisfy your power needs...for now!

Just to let you know that I will be doing a complete teardown of the engine and see if I can just get by with a hone or 30 over . I will also have the deck shaved a little . What is a good but reasonable kind of heads that you would recomend ?? Ie dart / world products/ iron eagle/ ?? And what's a good cam that will produce some good to numbers ?? Like a said ..... I'm wanting about 350 Hp .

I was 16, and my knowledge of engines was poor at best. I asked an Old Timer about how much it would cost to get 400 hp. He replied " Money is speed, Speed is money. How fast you want to go ??"

Thought I'd share that...

its not how fast i want to go , im not racing the truck . i just want some good tork and pulling power . but if the time comes to setp on it per say the horses are there .

Check this out for some dynoed combos to help get what you are after ............

http://www.ryanscarpage.50megs.com/combos1.html

Kitz

my 2 bits... if you're pulling a boat or looking for torque of any kind i wouldnt go for a super extreme cam thats going to cause you to have to put a high stall torque converter... get a cam thats going to give you good torque .. NOT horsepower. dont quote me on this but usually a good torquey cam is hanging the exhaust valve open longer than the intake... and are also good for supers and turbos if you ever wanna end up going that route. just make sure to match the intake manifold and the carb to the cam.

I picked this hydraulic roller cam below for my build and had it desktop dynoed... 400 ft/lb tq and 350 hp... granted the guy said his dyno is about 25 over on each.. but my weak spot were my heads and exhaust manifolds .. im runnin stock exhaust manifolds and my heads are the 76cc 1.94's... i matched it with the air gap intake manifold and HEI so maybe this helps you learn from my lack of budget.. go with some better heads that will get you a little higher compression than what i got and they will also give you better flow and that better flow will be complimented nicely by some headers. ps. my build was with a 97 block..

Duration @ .050" Lift(deg): I:222 E:230
Maximum Lift(in) w/ 1.5 rocker:ŕ.6 rocker" I:.509 E:.528
Lobe Centerline (deg): 112

the way I see it, you are only 60 hp away from your goal. did you store your motor properly? does it spin over fine? if so, I wouldn't tear it down for 50-60 hp, I would do a cam with a good torque curve. what is your intake? ignition sety up?. losing the engine driven fan for an elecrtic helps a little. header choice long tube vs short. etc. Guess what I'm trying to say is that you don't have a lot of ground to cover to get your hp goal. what are you towing for a boat? hell I towed my 47 ford back 200 miles of hills with my 3.9 v6 dodge. was a little sluggish on some big hills but we never dropped under 50. I know your crate 290 hp probibly is around 275 or so on torque . one last note if you don't have one, put on an auxilery tranny coller. my 2 pennies

Originally Posted by my77chevy

Well cash flo is always the finial way to hp huh? ahhh as long as i can keep it under 2000.00 i guess . im not looking to race this truck . its going to be a daily driver . I will be towing a boat (runabout) but when i put my foot in it i want to feel it if you know what i mean . the old 290 hp is getting a little to weak for me now .

It wouldn't be very hard to spend twice 2 grand for a good top haft.I suggest you look for heads for a 350 to have intake runners no more than 185cc's.

HP ratings isn't what makes a street driven vehicle whatever it is.Those HP ratings generally have a peak in RPM's that are not generally used in daily driving.As you said torque is the focus you need to look at.The lower the torque curve,the better off you are.

Yes,I read where you said you didn't want to stroke it.But for the shortest path to your goal and the budget you stated,that is within the range of possibility.Just by the nature of C.I.'s,torque in bigger C.I. engines happens in normally driven RPM ranges.Well the torque curve begins at a lower RPM in bigger C.I. engines.And hopefully without getting into a debate of longer connecting rods VS shorter ones,the longest connecting rod you can fit into it helps aid in building a lower torque curve because of the longer the pistons dwell at TDC.So a very mile 383 would easily get you to your goal.Oh yeah,the thing is for the people closest to you when they want to know why your 383 is so much stronger than theirs,well you can just leave out the fact of the longer rods.It will make you look like a pro engine builder.

One last thing-for a 383,your looking to intake runners at 195cc.You want to maintain the volume of the intake charge at lower RPM ranges.But try to keep in mind you can always do a update with a set of heads at any point.The stroke and at cost of 2 grand is another matter.That is a building block that needs to be done first.

In the interest of giving equal time on the subject of connecting rod length, I will submit a tutorial from Iskenderian....

Tech Tip - 2005
Rod Lengths/Ratios: Much ado about almost nothing.

Why do people change connecting rod lengths or alter their rod length to stroke ratios? I know why, they think they are changing them. They expect to gain (usually based upon the hype of some magazine article or the sales pitch of someone in the parts business) Torque or Horsepower here or there in rather significant "chunks". Well, they will experience some gains and losses here or there in torque and or H.P., but unfortunately these "chunks" everyone talks about are more like "chips".

To hear the hype about running a longer Rod and making more Torque @ low to mid RPM or mid to high RPM (yes, it is, believe it or not actually pitched both ways) you'd think that there must be a tremendous potential for gain, otherwise, why would anyone even bother? Good question. Let's begin with the basics. The manufacture's (Chevy, Ford, Chrysler etc.) employ automotive engineers and designers to do their best (especially today) in creating engine packages that are both powerful and efficient. They of course, must also consider longevity, for what good would come form designing an engine with say 5% more power at a price of one half the life factor? Obviously none. You usually don't get something for nothing - everything usually has its price. For example: I can design a cam with tremendous high RPM/H.P. potential, but it would be silly of me (not to mention the height of arrogance) to criticize the engineer who designed the stock camshaft. For this engine when I know how poorly this cam would perform at the lower operating RPM range in which this engineer was concerned with as his design objective!

Yet, I read of and hear about people who do this all the time with Rod lengths. They actually speak of the automotive engine designer responsible for running "such a short Rod" as a "stupid SOB." Well, folks I am here to tell you that those who spew such garbage should be ashamed of themselves - and not just because the original designer had different design criteria and objectives. I may shock some of you, but in your wildest dreams you are never going to achieve the level of power increase by changing your connecting rod lengths that you would, say in increasing compression ratio, cam duration or cylinder head flow capacity. To illustrate my point, take a look at the chart below. I have illustrated the crank angles and relative piston positions of today's most popular racing engine, the 3.48" stroke small block 350 V8 Chevy in standard 5.7", 6.00", 6.125" and 6.250" long rod lengths in 5 degree increments. Notice the infinitesimal (look it up in the dictionary) change in piston position for a given crank angle with the 4 different length rods. Not much here folks, but "oh, there must be a big difference in piston velocity, right?" Wrong! Again it's a marginal difference (check the source yourself - its performance calculator).

To hear all this hype about rod lengths I'm sure you were prepared for a nice 30, 40, or 50 HP increase, weren't you? Well its more like a 5-7 HP increase at best, and guess what? It comes at a price. The longer the rod, the closer your wrist pin boss will be to your ring lands. In extreme situations, 6.125" & 6.250" lengths for example, both ring and piston life are affected. The rings get a double whammy affect. First, with the pin boss crowding the rings, the normally designed space between the lands must be reduced to accommodate the higher wrist pin boss. Second, the rings wobble more and lose the seal of their fine edge as the piston rocks. A longer Rod influences the piston to dwell a bit longer at TDC than a shorter rod would and conversely, to dwell somewhat less at BDC. This is another area where people often get the information backwards.

In fact, this may surprise you, but I know of a gentleman who runs a 5.5" Rod in a 350 Small Block Chevy who makes more horsepower (we're talking top end here) than he would with a longer rod. Why? Because with a longer dwell time at BDC the short rod will actually allow you a slightly later intake closing point (about 1 or 2 degrees) in terms of crank angle, with the same piston rise in the cylinder. So in terms of the engines sensitivity to "reversion" with the shorter rod lengths you can run about 2-4 degrees more duration (1-2 degrees on both the opening & closing sides) without suffering this adverse affect! So much for the belief that longer rod's always enhance top end power!

Now to the subject of rod to stroke ratios. People are always looking for the "magic number" here - as if like Pythagoras they could possibly discover a mathematical relationship which would secure them a place in history. Rod to stroke ratios are for the most part the naturally occurring result of other engine design criteria. In other-words, much like with ignition timing (spark advance) they are what they are. In regards to the later, the actual number is not as important as finding the right point for a given engine. Why worry for example that a Chrysler "hemi" needs less spark advance that a Chevrolet "wedge" combustion chamber? The number in and of itself is not important and it is much the same with rod to stroke ratios. Unless you want to completely redesign the engine (including your block deck height etc.) leave your rod lengths alone. Let's not forget after all, most of us are not racing at the Indy 500 but rather are hot rodding stock blocks.

Only professional engine builders who have exhausted every other possible avenue of performance should ever consider a rod length change and even they should exercise care so as not to get caught up in the hype.

http://www.iskycams.com/ART/techinfo/ncrank1.pdf

Actually Ed and us had the same discussion over dinner after a auction that John Lingerfelter(sp) was holding selling off 25 yrs of collected hot rod parts.We met Ed originally at a Indy Drag Racers auction 2 yrs before.It was John's operations and business that convinced me of the longer rod theory.At that time John's builds included 5.85 length rods with comparative dyno results.Hands down the 5.85 produced a great torque curve and a broader torque ban at a lower RPM.On the cheap-there was a method of using Buick rods that where 5.85.Currently John's company uses 6.0 rods.Now I know Ed Has been around forever,but John was and his company is the innovator on the cutting edge for a long time as well.From what I have seen from Linerfelter's(sp) and used in a drag race operation where E.T. gains where found with longer rods,well I am a believer.Well the other question is why then are stoker kits universally using 5.7 rods and not the shorter 400 rods??.Humm,must be something to that.

Oh yeah,God Rest John's soul.He was one of the good guys for sure.

well i will add to this. longer rod are not to big of a deal . were you will see a longer rod is for more counter weight on the crank that helps get the mass were you want it with out a lot of heavy metal nailed in to the crank .some times you just can not get the rod you may want to work with out a very short piston with a very short CH . all this has a bit of what your going to do with the engine.one engine i am working on has a 7.680 rod

Pat,when you go to the 6.125 or more yep you can get into ring problems,but with the buttons that are out there,it is a non issue.Anything under a 6.0,you can get good results.Remember,almost all stroker kits use a 5.7 rod for a good reason.The others are even longer.Non are the 400 size.