This is the final episode of the budget build.
We had originally planned to advance, and retard the camshaft on the dyno but, due to excessive leak down on 4 cylinders we decided to do these tests another day to provide more accurate data. Testing with this issue could prove inaccurate data, as it is difficult to quantify the effect it would have on HP/TQ.
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My guess on the 2 barrel was 30hp and 20tq down. Strange it lost more torque than horsepower. I've seen 550+hp 355s lose 70+hp with a 2 barrel. Should have tried a 750 doublepumper and a 750 3310 vacuum secondary carb also. Might have picked up a few numbers. 350 LT-1 came stock with a 780 vacuum secondary 4150 carb. They were rated at 360hp in the Z-28 & 370hp in the Vette. They actually made in the 350+hp range bone stock on a dyno with headers.
Great content! I always enjoy your videos. I have been a diy mechanic for over 30 years and have never dyno tested anything I have built. This really puts it into a realistic perspective as to what to expect from a similar combo. I never tell anyone how much horsepower I expect an engine I build will make bc there are just too many factors that can affect the outcome.
350hp/400tq fresh SBC for $1600 bucks is a good deal.
Awesome video series! Enjoyed and learned something from every video! Thanks
1hp per cu-in on old style iron heads is still respectable.
Looking forward to the next one.
Nice work Darrel Watters! Next time make him sit on a chevrolet chair!
My DD-5 was way high on TQ. I changed the cam to ICL 108° and switched from Large tube to Small tube headers:
356hp @5000
423tq @2500
***Highest HP and highest HP/TQ Average I had to change the ICL to 111°
great series, I have to make sure I watch all10 vids. Cheers from Calgary.
Nice test but a little disappointing on power …. Dyno cell did not look like it has a lot of exhaust room but a muffler might have helped and I assume the engine will be run with full exhaust system in the car….. If you do pull the heads look for fuel wash in the chamber …. With unknown port work that funny low rpm dip you got could be from fuel dropout …. With that camshaft and what you saw at peak a 1.5 rocker on the exhaust side only would probably help ….. Also flow cfm on the hat is not the same cfm as a carb measured with a pressure drop though your carb size should be ok … Did you run a spacer? 1 inch open might help peak
I'm liking this series, very well done.
A lot of things have to go right to have a good running reliable engine.
That's a cheap investment for what your doing to get the power you are happy with. If I build an engine for someone I tell them approximate how much HP they can expect out of it. It all depends on what parts are put in it. There is a few variables… My BBC is a 468" engine, strictly a race car engine. 12.3 comp. Solid roller cam, SV1 carb, 1150cfm, BB-2 Brodix heads, 310 cc. Single carb one barrel. The parts are new, but they are over 30 yrs. old. Makes good HP, 800+. It makes 1.7 HP per cubic inch. It's fast for what it is. 66 Chevelle tune chassis and is light, 2,370 lbs. with driver. 5.40's et. in 1/8 th mile at over 125mph. And 8.60's et at 155mph in the 1/4 mile. I have a big engine Iam building that puts out around 1,300 HP on alcohol methenal, with 15:.1 compression with flattop Pistons. Power range on cam is 4,000-8,500 rpm.
Oh! Allen, I forgot to add that I believe I have the right combination to make my car run as good as it does, 60 ft. times are 1.20 et.
Oh! Allen, I forgot to add that I believe I have the right combination to make my car run as good as it does, 60 ft. times are 1.20 et.
Dyno testing is a base to start with Allen…
You can change the spring in the oil pump to lower the oil pressure and if bearing clearance is too tight, use bearings that have .001" extra clearance, perfect bearing clearance for small block should be .002" on rods and .0025" on mains.
You always get more low end torque with longer collectors…
Allen what lobe centers did you install the cam on?
I dont remember? Did u guys build the heads urself? I guess im wondering why the exhoust valves were leaking? It happens i know. But did u have a shop cut the seats or did u guys do them urself with stones?
Great video though! I love it when people do real diy builds! Builds using oem iron heads are much more interesting to me becouse thats my caliber. Thats what i relate to because thats what my builds are like. This is the best! The only way it would have been more relatable for me is if it was the same, but with a ford FE. Thats what im workiin with in my shop.
You will probably see less leak down now that the motor has been run. Curious to see.
300 h.p. at 4000 rpm with 50 more and good torque also. The rings are sealing up the friction in the motor will lessen a little with miles and when you fix the leaky valves it gonna get the 375. And Nice idle drive ability engine. Good video thanks.
I know it’s costs a lot money but it would be nice to see what engine does with hood leak down. Information sake.
I would like to see the same sort of build on a 351 cleveland as a comparison to a 350 chev
Would you consider doing a video on the small block chevy 302?
You're still making >1 Hp per cube inch so not too bad considering the modest Build Budget…..Wish youall would've Killed a good Leak-Down Cylinder & Measured Power drop & Compared to one of the Bad Leak-Down cylinder to Determine Exactly how Much the Leaking Valve cylinder is Actually Down on Hp if any Significant…..Some Leaking Valve Cylinders produce Amazing Good normal dyno Hp…..As is, the motor seems to be Producing about Average power Results for a Typical DIY garrage Build…..
Hope you do a video on what got messed up on the heads, makes you wonder just how good the whole valve job was, could be power in getting some decent seats and angles cut, back cut intake valves ?
Reduce exhaust duration to make more power, that'd be a first, fuel out the exhaust, well yer, the exhaust valves aren't sealing.
Very comprehensive garrage Build & Dyno test Results on this 350 Chevy…..The unfortunate High Leak-Down cylinder Issues is Why I like to Leak-Down test all heads Before Engine Assembly by Clamping a 1/2" thick Sealing Plate (with appropriate Gasket or rubber O-ring) to Each cylinder head Deck Combustion Chamber & performing Leak-Down test to catch All cylinder head & valve job Leakage Before Engine Assembly…..This way Each cylinders Total assembled Leak-Down # can be Identified & Evaluated to Valve job Leakage or Piston ring/Bore Sealing Seperate categories…..
Looking at the dyno sheet VE numbers are wrong …did you have the wrong engine cid punched into the software? VE on that engine should be in the 80s
I put basically the same set up in my 1983 chevy c20 truck project. Same cam and all. Lol. I made 350 as well with the ported stock heads. So I'm happy to see the same results. I wish I could share pictures in your comments. Nice build Allen. Looks an sounds great !!!
A set of bone yard vortec ported heads would put it close to 400. Casting 906
I knew it was going to make a good bit of torque from down low!! I could hear it in the other short!! This is not bad at all!
Good enough to burn some tires and have some fun with around town, especially if hooked up to a 4 speed!