1969 Engine Uprgrade Suggestions

S

steelpontiac

New member
I have had a great running 1969 Pontiac LeMans Custom S for about a year now and am finaly ready to start throwing some work into her performance. I will be pulling the drive train to throw in a new trans (already have it) this winter when the car is off the road, and wanted to upgrade her performance while I have the car in pieces. Its a weekend driver so nothing real high end but what are the best suggestions for parts to upgrade for better performance to handle the 0-100mph speed range?



Thanks for the help!

-Steel
 
Yes it is stock, I believe Pontiac didn't have specific big/small blocks like Chevy even though its all GM, but it is a 350, I picked up relativity new 3 speed trans so cheap it too good to refuse, but am keeping my eyes open for a 3 speed w/ overdrive (2 speed in her now). I also already have a dual exhaust (2" pipe) w/ flowmasters to put in. I also will not change the look of the car (other than wheels) for performance I would rather leave it stock if I have to, my thing is stock look but modified inside. My performance goals are for it to be real quick off the line up to highway speeds but I have no need to be flying around at 150mph.My budget, this is my only real expense I can put in 1000-1500 but that is pushing it.

What do you think?

Thanks
 
yes Pontiac used one basic size block for everything, with the exception of the later 265 and 301 low deck motors (as long as it is not one of them you will be ok)



so the tranny is an auto?

if so you need to do some thinking about what you want to do



I would start with a higher stall converter(but you will need to match it your cam and powerbandto get the most from it)



for that $ I would try for

stall converter

shift kit

cam

as much head work you can afford
 
One thing that makes a good difference, and is the basis of any engine upgrade, is to make sure it is in a good state of tune to begin with. Change the plugs, wire, upgrade to a HEI distributer(less than $100), make sure the carb is in good condition and opperating as it should. Possibly invest in a leakdown test for all cylinders. then you can start improvements.



If you are handy changing your cam and lifters is a good saterday job, with spectacular results(by far the most bang for the buck), high ratio rockers are almost free HP, but be sure to match the cam to your expected goal, carb and drivability range.



IF you have a 2 barrel carb, chnaging the intake manifold and carb for a 4 barrel unit will do a world of good as well.



If you find that the base needs some work(low compression, loose bearings ect, you can look to your local race track for a good engine at a affordable price. If you have a local track that runs GM spec engines, many teams elec to change them every year, a new engine is around $3500, amny 1 season engins sell for around $1500, and once off the track will last for years if it was well maintained(look for a front running team, they usually keep things straight).
 
The trans is an auto but I dont want to go playing with the guts of one of those. How much would it cause to have a trans built for what you were saying BigJim? If its a lot, and i could get by reasonably with a 3 speed or 3 speed w/ overdrive i would like to spend on a carb/intake/rockers/etc.

Speaking of engine parts like you were talking about Reparebrise, i replaced the rotor, cap, wires, plugs when i first got it because she didn't fire well would replacing the entire distributor make a noticeable difference over just those parts? I have been looking at a holley 750 cfm 4bbl carb but that requires a manifold to fit it the 4 (my manifold fits the 2bbl rochester on there now) how to i go about finding a manifold that will fit?

Thanks guys this is great!
 
well the stall goes between the trans and engine so it not the "guts" of the trans

and a shift kit is a D.I.Y. if you can read and are not affrad to drop the pan
 
Okay what would you recommend for a stall, cam and shift kit? And as far as head work goes are u suggesting getting new lower heads or what can I do with the stock ones?
 
new heads are not in you budget



stall IMO prob about a 10" 3500

but it is really going to depend on how crazy you go with the cam, how much power the engine makes and where in the powerband it makes it's power



the shift kit is going to depend on how hard you want it to shift
 
On a mild 350 750cfm is way too big, if you want good street power a nice Hp series 650 cfm will do the trick, and yes a HEI distibutor will help, no points= no hassels.
 
go to the holley and crane cams web sites, they have good web tools to determine the good mix of parts, think of the carb as the lungs, and the cam as the brain, even though your brain sais breath, if you have cold sometimes the lungs don't co-opperate. An engine is a system, where every part affcts the other, too much carb for the cam or too much cam for the heads will make an engine worse, not better.
 
Okay from the top...



A three speed with overdrive is a 4 speed like a 700R-4 (TH350 with an additonal gear). GM put these in everything in the 90's and you can pick one up for pretty cheap now. Not sure how they bolt up to the Pontiac engines but I don't think it is too much of a problem.



As far as the motor, why not drop a 400 or 455 Poncho in it, or even bone pick a 350 Chevy from the junkyard.



If you want to stick with the 350 Poncho and just add a little power to it (it will never be fast) you can throw a set of headers on it, an intake, and buy a book on how to tune a carb. Then tune it well and you should push 240-260 net horsepower, which isn't a ton, but will move the car out nicely.
 
BigJimZ28 said:
new heads are not in you budget



stall IMO prob about a 10" 3500

but it is really going to depend on how crazy you go with the cam, how much power the engine makes and where in the powerband it makes it's power



the shift kit is going to depend on how hard you want it to shift
Click to expand...



If you are sticking with stock heads (which don't flow well on the 350 poncho's) then you are going to want to stick with a mild camshaft (likely similar specs to stock but with a little more lift and a more aggressive ramp). In this case 3500 might be too much stall and make the car feel lazy around town. Keep the converter as tight as you can on a daily driver and focus more on tuning and throttle response.



Small cam, headers, intake, 650 carb...
 
A set of long tube headers preferably ceramic coated headers, they last longer and run cooler. All the other mods will only add little power to the power band if the engine can not exhale. Let her breath. Whatever is left over money wise swap out the intake manifold (grab one used off ebay and clean it up) and a new 4 barrel carb. A 600 cfm will work with a very mild 350. I'm sure Year One and the like sell conversion packages that include everything you need.

Looks l
 
Everyone thank you I appreciate your time. I think I have an idea of what to look further into now. If anyone has any more suggestions please throw them up for me.
 
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