Rethinking my pizza 355

[85 Cutlass Brougham]

This may seem odd, but back when I first did the engine swap on my 85 Cutlass, I built the engine with pizza delivery in mind. Back then, it had a 231 V6/TH200C 2.41 axle combo in it that left alot to be desired. So, I built this 355 Chevy with driveability and mileage in mind. The specs are as follows: .030 2 bolt main block, cast crank, stock rods, ARP rod bolts, Cast rebuilder pistons, 9.5:1 Compression, World Porducts S/R Torquer heads with 2.02/1.60 valves, a Crane emissions cam for a 305 with 210/216 duration, 440/454 lift and 114 degree lobe seperation, "Z-28 " oil pump, Edelbrock TES headers and Y pipe going into a single 3 in cat and going back to a Dynomax catback. It had a stock 305 aluminum intake and a computer HEI that were leftovers from a 406 swap in a friend's 84 Z-28 as well as the rare factory dual snorkel air filter housing and ducts that I topped with a Monte Carlo lid so I could run a bigger filter. I also used an oil cooler setup from a 9C1 ( police) Caprice. It originally had the E4ME Q-Jet and computer from the Camaro as well., and was wired with a Grand Prix 305 harness. It actually ran pretty good, breaking down but once in the 50k miles I delivered with it in the next year ( don't use bargain rocker arms!). I have since added a $15 Edelbrock Perfromer I scored at a U pull it yard and a non computer HEI and Q-Jet. It has great low end and pulls nicely all the way to 5500RPM, but I am left wondering if I could do better now given all the advancements in parts that are available. I am thinking about a roller cam and aluminum heads, maybe a different intake ( has to retain the Q-jet and air filter housing- I hate open elements, too much maintenance), or even stroking it to a 383. I can get roller cam 350's on occasion for $75 for the shortblock ( same junkyard), but was wondering how anyone else would build an engine for these conditions? Has to have a smooth idle ( right now it idles at 750rpm), decent fuel mileage, able to have most minor tune up items replaced with parts store pieces, etc. What would you do to improve the current combo without sacrificing driveability ( and without nitrous)? Oh, it has a TH200 4R and a 3.23 rear going back to 245 50 16's, and is fully optioned and must retain all the luxury stuff and A/C. It's kind of an academic question, but I am interested to hear comments and suggestions as I am currently working on the car and trying to run 13's.

 

[Cutlassjim]

When looking at what to do next I always like to think what will give me the most bang for the buck and what will compliment my current setup. Like yeah you could go and get a sick set of aluminum heads with huge valves, but throw them on a stock motor and your gonna get bupkiss for results.

Anything that helps get more air in and out more efficiently will give you more power AND better milage but it sounds like you've got a pretty good intake/exhaust right now. A different intake would probably only shift your powerband losing drivability.

Usually a roller cam is used to get a very agressive profile. High ramp rates from the rollers = more duration and overlap = rougher idle, shift in powerband, loss of milage.

If your running a high temp thermostat a 180* will help power a little and still give decent heat. I've found a nice aftermarket high-output ignition coil help the car start and idle better as well as feeling "stronger" in the entire powerband. An electric water pump will save a few ponies but you gotta think about $ per HP with that.

It's tough to have your cake and eat it too unless you resort to turbo, nitrous.

 

[383Camino]

Electric fans, underdrive pulleys, 1.6 roller rockers.

 

[85 Cutlass Brougham]

Well, there are numerous reasons for the heads, some of that is a need to reduce the amount of weight over the front wheels as this is a handling oriented car, as well as being a driver.( I already installed a aluminum hood off a diesel car, and have Eibach springs, ES poly bushings, an IROC-Z Steering box, and the factory big swaybars) Also, the new heads would give me a better combustion chamber design and reduce the need for timing, have smaller chambers and raise compression etc. To that end, I considered using a set of the Vortec heads or the Edelbrock E-tech heads. I didn't mention that the car has a MSD cap, rotor and digital module that fires an Accel coil and goes through MSD plug wires. I tried an MSD 6AL off my other car on it and saw no appreciable difference.The 1.6:1 ratio rockers are in the cards as the next modification, but I have yet to decide on which ones to use. I want to stay with the stock 84 305 valve covers, so poly locks are likely out of the question ( but I haven't checked this either). The engine bay looks like all stock 305 stuff except for the headers, and I like that. I have considered using other flat tappet hydraulic cams like the Comp Xtreme Energy line ( XE262 or 268.....how do they idle?) as an upgrade since I already have decent valvesprings ( but then...the engine sat for 5 years so how good are they now?) According to an old dyno sim I have it makes 343hp and 400 ft lbs which isn't bad, I just want to see where I can improve on it and keep it as a nice street engine.Then again, I may build another engine in the future and build it for nitrous as I an uncertain about the cast pistons.

 

[85 Cutlass Brougham]

Oh, and the car also has a 160 degree thermostat in it. As for the roller cam, I wanted it for a more aggressive profile with more area under the curve for a given duration as compared to a flat tappet. I could still have a cam with 220 degrees duration at .050, but with significantly more lift and a faster opening rate for more airflow into the cylinders, while still having short overlap and building decent low RPM cylinder pressure, thus maintaining idle quality ( which is why I like the 114 degree lobe seperation on the current cam as compared to the more normal 110 degree LSA on a typical performance cam). This in addition to the higher static compression allowed by the aluminum heads and better combustion efficiency, should keep my desired 750 RPM idle speed, as the higher compression ( 10.5:1 or 11:1 is what I want) should compensate for a larger cam at low engine speeds.
I have also contemplated long vs short rod theory and the affect that it has on detonation, RPM range, etc. but decided to just build a cheap 5.7 in rod 355 or 383 as it likely wouldn't provide a significant enough difference to offset the additional cost. Well...build on paper at least. I'd still need a much better rearend and a built TH200 4R to reliably handle significantly more power than I have now, so that would have to be first.

 

[RedHotRegal]

6" rods

the longer rod delays peak piston speed, and thus peak air demand, till later in the stroke, when the intake valve is open further. if building a long stroke 350 block (383) the 5.7" rods come in contact with the block just below the bores. They may also come into contact with the outer walls of the block, and also may contact some cam lobes. That is right out of "How to Build Max Performance Chevy Smallblock on a Budget" by David Vizard.

 

[steve 86]

At the risk of repeating my self from a previous reply to a different topic... dont over think it. I.M.O., forget a roller cam, they cost big $$ and usually are too agressive for good drivability and the ones that are drivable,well...you can get better performance w/flat tappet. You're on the right track with new heads, and vortecs are a pretty good bang for the buck but remember you need a vortec intake,but still its pretty cheap.
Keep in mind, an engine is an air pump, the more air it can push out, the more it can take in, so if you can put true duals(no catts.) that will make more power than an over agresive cam. Once again this is only my opinion but its based on experiece.
Theres alot of power to be found in carburetor selection. get a Holley.......I know alot of people dont like them, but thats what all serious racers use and now a days they are pretty reliable.
If you dont have a stall converter, dont get a huge cam!!.......IMPORTANT.....for every 10 deg. of duration at .050 you go up, your power band moves up about 500rpm. so if you have [email protected], your cam doesnt turn on till about 3000 rpm.( but thats not to say you cant over do it a little :wink: ) pick your cam according to that.

there are alot of other things to consider but these are the basics.
Also, i read that you dont loke alot of timing? . timing is your friend, and a good one if you dont abuse him, but thats a whole nother post.

One more thing, use a dual pattern cam (almost always!)

 

[383Camino]

I like this guy. 8)

 

[85 Cutlass Brougham]

My biggest problem with the Holley is that their idle circuits suck. I have one on my AMC 360 ( 3310-750 vac sec.)and hate it. I'd put a Q-jet on it if I could find a spread bore intake for an AMC.It also won't allow me to run the cruise control, TV cable etc with stock appearing parts and the stock air cleaner I use ( L69 Camaro dual snorkel) won't fit the holley either. I have an Edelbrock Perfromer 600, Holley 750 vacuum, Holley 600, and one of those "new" style Holleys ( R84016 and 2250 are stamped on the choke horn) in a 650 Double pumper with spread bore configuration laying around ( I love my neighbor's throw aways!), but really am in love with the Q-Jet's part throttle driveability. I have had the 750 vac sec and the Edelborck 600 on it, and neither one was as driveable or good on gas as the Q-Jet ( I run the E4ME primary throttle shaft on the 79 Buick Q-jet for the linkage). I plan on having a local carb shop with a good reputation go through a Chevy style Q-Jet in the future ( rt angle fuel fitting).I also don't like open element air cleaners and any sort of chrome under hood. Too much to clean, and the air filter elements go bad too quickly. As for a roller cam, the one I was considering was the GM LT4 "hot " cam , and I would likely not put a cam with over 225 duration at .050 in it. ( but I forget what the specs are on the LT4 cam...). I do need a new convertor and plan on using a 2500 stall lock up convertor ( has a stock rebuilder one in it right now-12 in), if I don't swap it out for a T56 or a T-5 manual ( I like driving manual trans cars better). Then again ,this is where it gets expensive so I dunno what I'll do there.

As far as timing goes, I don't like it in a cam because of the poor idle quality. I'd rather have more lift for a given duration. Oh, and it does have a dual pattern cam right now. ( 210/[email protected], 440/454 lift) It's almost purely a street car which may see an occasional test and tune night but will never be raced competitively. I tried using a big cam, etc in the AMC and didn't like the results as the car is fairly undriveable and doesn't like to idle for extended periods of time. That, and the low ground clearance of the full length headers, the lack of an overdrive, no A/C, no sound deadener, electrical problems, failure of 2 Holley blue pumps, etc make for an uncomfortable ride on long trips -or when I was forced to use it to deliver pizza . I am basically trying to determine the threshold of irritation with the Cutlass without stepping over it and to see how much I can get out of the car with a stock like driveability and idle. I really don't want to build another car I hate to drive so much that my 4cyl pickup truck seems like heaven.