I have a 94 corvette. Recenty I toasted my rod bearings in the stock engine. I built a 302/LT1 last winter for an IROC...but car is far from done and am thinking of scraping that car. The engine runs and sounds great. You can see it run on youtube under vfr800fi07 username. I was usuing a manual trans for it. Engine specs are 11.2:1, comp 503 cam, and 21* trickflow 185 heads. I am gonna run with 3.73 gears and it has a 4L60E trans with a yank SS3600 stall. What do you guys think of this combination? Would you like updates on this? The engine was built with L99 crank and rods..with icon 6.3cc domed pistons for vortec style heads...by the way I heard there is somewhere I can have my tach overlay modified like a LT4 dash. Info on that would be great.. thanks.

 

so, you;re saying you want to put the 'built' 302 in the Vette?

going backwards IMHO.

it might rev like a chain saw but it will lack the torque of more CI. I've never seen a smaller engine do well in place of a larger displacement...even when built. It will struggle more, and the power band will be.......different. Might be ok for a grocery getter...but I have the feeling that with all that stuff thats been bought and installed you want it to do a bit more.

Go search out a fresh short block and start building a 350, 383 or more for the vette. Sell the 302 to somebody that can use it and junk the irec. Just my opinion...its gonna be your call.

 

Vette should be lighter Id guess, probably wont be breaking the IRS either. Id put 4.11(at least) and the stall in it let it scream.

Cubes are always the answer but not always affordable.

 

Well I am predicting 12's with this engine..it was built with forged pistons and I have a 150 shot to add to it.. The redline shoud be between 6800 and 7000. If the engine doesn't produce, next march I will do up the engine that was in it... its just I built this 306 and am curious to run it since I am **** canning the camaro.

 

Sounds like fun, put it in and run it, a built 302 can be fun and make great power.

 

Well now that I think about it...I am not too worried about low torque issues.. the 350 had a torque converter ratio of 1.8:1 and rear axle had 3.07 gears. The yank has a 2.5 ratio which is over 20% increase and a 3.54 or 3.73 is another 15-20%. I guess since an engine is a air pump given the cid difference I have to rev roughly 800rpm over 6300rpm to make the same power up top.. I am gonna run it and see.. should have it done by end of week.. hopefully get the tune done too by then.. I believe with the slower piston speed and 1.98 rod ratio an xtra 800rpm would be nothing to the bottom end..and I suppose if this thing kicks *** it would be cool to say its a little 306. And the exhaust should sing nicely..

 

Ok results of road test... Engine performs way better than expected. I notice no lack of torque down low. Driveability is great. Its very smooth past idle. Its like 2 engines..very mellow at low rpm and smooth..around 4k and upreally pulls hard.. I only did this once out of pure curiosity. Not enough miles yet ran up to about 5800rpm. And only 3/4 throttle. Cruising at about 70mph its getting 28mpg.. and that's with 3.54 gears.. I don't think it'll have enough miles on it to run it at the track this season..but spring time I will..it definately drives better than the 350 that was in it. Also I put a yank Ss3600 in it.. I really can't wait to get this thing broke in and rapped out to 6800..I am very satisfied with this engine...I was skeptical myself.. after enough miles I will add the 150shot to it..and I found a LT4 cluster..should get that in a day or 2

 

If you got 50 mi on it no problems and the tune is on then take it to the track.

 

Well its got 120 miles on it now. I took it to work today and was in Chicago rush hour traffic without a hitch. Madtuner did the tune. No hiccups. I got vavoline 5w30 dino oil in it for break in. I would like to do at least 500miles. Then change to the Mobile 1 oil, before I jump hard on it. I also just put the 3.54's in and a recommended break in was 20 miles..cool down..then 100 miles before hard acceleration.. Oh..also what is the norm for a new engine's oil pressure.. I got at normal operating temp 25psi at idle and as soon as I tap the throttle 40psi..and at cruising speed 50-60psi..thanks

 

Ok 500 miles on engine put mobile 1 in it and ran it up to 6500..got a video of it on youtube under vfr800fi07 screen name..I like it..just have a bit of traction issue..but I'm just 2 tires away from that..

 

Video clip of run up to 110 http://youtu.be/maIocXMTCEA

 

what is the length of the crank throws ? i.e a 350 uses a 3.48" throw, a 327 (if memory serves me well) a 3.25" and your 306 ?

 

Oh.. I used L99 5.94" rods and L99 crank 3" throws.. which gives a 302 unbored and 306 .030 over.. also stock pin height 350 pistons..I used 6.3cc domes for vortec style heads to bring compression back up.. also the chambers on the trickflow heads are 54cc.

 

I really like that you used a (nearly) six inch rod; with the three inch throw on the crank, it should move your rod to crank ratio into the neighborhood of "fabulous" which probably goes a long way towards explaining how well your engine runs. Any (before / after) mileage figures on that lil' puppy ?

 

I re read your thread; 28 mpg ain't nothin' to sneeze at with an auto. good job.

 

Well the original engine with the 3.07 gear was around 24/25 mpg..and with this engine it has 3.54 gears. The engine seems to pull a little harder as I put more miles on it... I really love the way it runs..the only thing I am contemplating is removing the resonator so this thing can sing...its got the stainless magnaflows on it right now..not sure yet..don't want it crazy loud.. a lot of people that tried this build went with stock lt1 pistons and that yeilds under 9:1 comp..that's probably where they went wrong.. I would recommend this build for something different. This engine was originally built to go behind a stick..but it does well with the auto and SS3600 stall

 

Thats right about what it should be. Default max is 80, (never happens, bypass opens long before that) so warm idle at 20+ is good, instant response to throttle is great...cruising speed of 2000 w/50psi is perfect.

Considering the lt wt oil thats in there now, its doing what it should,.
Thats pretty much exactly what mine does, difference being mine is 377ci, runs 5-30 (winter oil) and has close to 200K on this build.

I think the biggest indicator of a tight bearing assy and good pins/rods is how the oil pressure responds to rpm changes. Instant increase when warm tells me the oil is staying in the passages and bearings and not being lost to wear leakage out the sides. If there was hi wear, then OP would be slow to increase as much of it is being lost between the pump and the sensor.

OP on the gauge is really showing you what was not lost in transit. If you see 50 at 2000 rpm and it tries to climb with more rpm (can't because of bypass) then its as good as it gets. After break-in it should be very similar although it may be slightly higher IF you go to a heavier oil.



Congrats on the build. I would not have thought that the smaller CI would run that well. And you have the bonus of higher rpm, likely to be smoother and you;re not even juicing yet...ought to be fun!

 

Thanks for the complements...trust me I was taking a shot in the dark..spending money on balancing, machinework, and all the parts putting this thing together..basicly a gamble... trust me I was nervous the 1st time I put it to the floor fearing it wasn't gonna have much more power than at 1/2 throttle..whew!! Glad that's not the case.. I believe it will respond well to the N2O.. in spring I will bring it up to get it dynotuned..I am sure there probably is a little more to get out of it since it was just a mail order tune to get me started.

 

Results at the track was 13.5 at 102...had to baby it out of the whole cause of wheel spin...I guess not bad for 306cid. Stock manifolds.. I think with headers it would be quicker.. that was at 6500rpm and no nitrous... I just got done building a 383 so the 306 is going in my sons 95 camaro cause he wants it now...and though I was impressed..of course I wanted more..so my 383 shortblock is an all forged bottom end..running a xfi280 cam and putting the trickflow gen x 185 heads on it..compression 11:1. I'll keep you posted on both engines as they come along. Gonna throw the 150 shot on the 383 as well