Hey guys, new to the forum, and just wanting a bit of advice on my truck. I have a stock 77 chevy and I am getting ready to give it some upgrades. The truck will mostly be used for pulling my boat (18ft cntr console 2500-3000pds trailer weight). I was just wondering what engine upgrades would be good to help this engine pull the boat. Im tired of watching my speedometer needle fall when I hit a two inch incline pulling my boat (how my 95 truck reacts when pulling the boat). On the same note I will be doing a tranny swap and was wondering what you guys would recommend (Ive read other posts but none seem to address towing). All my buddies own diesels and insist that I cant get this from a gas powered engine and that I have to go diesel (Im being stubborn and refusing to concede). Current Setup: SB 350 3.73's TH350 (having some problems...needs an overhaul) 4bbl Rochestor (getting ready to convert to TBI) Budget is some concern so big $ crate engine swaps are out. Thanks alot guys.
As far as the tranny, a TH350 is fine, but since you are already swapping, if you could find a TH400 then that would be better. Also a trans cooler is a good idea. The bigger the better. 3K lbs is pretty light, but a swap in gearing to 4.10's would help with towing, but gas mileage will decrease. As far as the engine, you wont get any more power from the TBI over a properly set up 4bbl, but driveability will GREATLY improve, so that's one mod you will never regret. A set of long tube headers and a nice dual exhaust setup will help out when towing too, but that stuff gets pricey real fast.
I have a few conflicting reccommendations. 1. DO NOT use a TH400, they are power hogs. Their parasetic drag is much higher than a TH350. With that, you don't need a TH400, they were designed for the 454 where people would be towing near 10K. A TH350 can easily handle your small block and a light load like your boat. 2. I'd leave the carb on it instead of TBI. The carb is easier to work with and you are wanting more power. 3. Have the trans gone through and have any updates or popular upgrades done to it, and definantly some sort of shift upgrade. If fuel mileage is a concern, look into a TH700R4 conversion for overdrive. 4. Put a new cam in your engine, this will really help WIDEN your power curve, along with adding more peak power. An aluminum dual plane intake manifold, headers with either a 3" single system or duals. A single 3" system makes just as much power as a dual setup and saves mony and weight. It would be your call to reuse your current carb if it's in good shape, go with a new carb, or go ahead with the TBI if you can make it work with the engine mods. This setup should let you pull most grades at the speed limit. Yeah, the diesel guys are still going to be able to outpull you if their boats weigh the same, but you should be able to manage the speed limit, which is plenty.
Upgrades I would agree that the th350 is better than a th400, if your truck is a 1/2 ton (you didn't say). If you wanna swap to efi I would do a tuned port system over a tbi. It makes more torque than a tbi and it cost about the same, since you have to buy intake, throttle body, computer, and fuel pump. I would leave the gearing alone unless you have a 4x4.(you didn't say). Good luck! Eldogg Queen City Speed
just have your 350 rebuilt to heavy duty specs(police,rv,trailer towing) basically one build level above stock form. youll have firmer shifts that are quicker than before and cheaper on cost than a full out perfomance transmission. make sure you have your torque converter,cooler, and lines flushed out before reinstalling, any left over pieces from the original trans can destroy your new or rebuilt trans fast. my 1975 tows an 18foot dovetail carhauler with a 1981 grandprix dirttrack racecar. car alone weighs in at 3400 lbs so you will be just fine with your boat. happy haulingwaytogo
Thanks Guys Thanks for all of you guys input, Im trying to decide which cam and manifold I want to go with...any suggestions? Keep in mind it will be TBI, (conversion is cheap and easy, and saves on gas). As far as exhaust goes I already have a dual set up in mind which will greatly enlarge the exhaust flow. I have run in to one minor hitch though..Im gonna have to pull the engine to do the cam and manifold, but my old headers are rusted solid..any tips on removing old rusted header bolts? Ive tried some penetrating stuff but I still cant budge them, not that Im just cranking down on my break wrench (dont relish the thought of drilling out bolts). Oh and after careful comparison and consideration Im thinking about leaving my high gears, 4.10 would kill and I do mean kill my gas mileage....pulling 3k to much for 3.73's? Thanks again.
On the header bolts get the bolts hot or after driving a long trip spray on a good coating of wd-40 let it sit over night should work wonders. My tips on a cam would be an rv cam check out comp cams and rebuild your current tranny or have it rebuilt with a shift kit,better converter,cooler and see if the builder can slip in some extra clutch packs and a 4.10 or higher,well really lower,gear but the 3.73 should work for what your looking to pull and try to keep the carb if you can yes fuel injection is leaner therfore makes more power but your properly tuned carb should work wonders. www.compcams.com
If you change your gears that would make a big difference in the way it pulls. A small RV cam would help a good deal too. Rick
TBI is a fine injection system, but it's a PITA to adapt to modified engines. Unless you're willing to get down with the laptop and mess with stuff, I'd stick a truck avenger or aftermarket Q-jet on it. Or TPI if you're set on injection. Rebuild the TH350, put a cooler and gauge on it. I'd recommend an aftermarket converter too. Put some vortec heads on it and run an edelbrock performer manifold. If youre going to rebuild the engine, put an inexpensive cast crank 383 setup in it. Call comp's cam help line and ask them what cam you need. 3.73's are fine. Finally, put a good HEI on it and headers/ exhaust.
