If i want to build 350 motor up between 350 and 400 horse is it possible to use stock heads. With some decent machine work done is this an attainable goal. If so what kind of heads should i look for. Specifications or serial will do. Any input will be appreciated. Thanks

 

sure you can do it with facory heads, l98 heads or vortec heads come to mind as possiable heads.

 

#14101081 are these heads any good or are they junk

 

They are good heads...and after good porting will NET you over 400 horspower with proper combination of engine components.

 

Thanks for the input, i also just got offered a 91z 350 motor. Would this be a good base to start from.

 

Yes, of course.

Even with unshrouding of those heads, though...Expect some potentially high compression numbers for a 355ci engine...in excess of 10:1.

I'm stepping over my boundaries of knowledge a little here, but in achieving a quench of say 0.039 by a felpro head gasket with a bore of 4.166 and a zero decked block. A 58cc head increased to say 60cc after unshrouding and surface milling nets a compression ratio of 10.6:1 using -7cc flat tops. Something to consider. Not sure the best way of bringing that down.

 

ok, So the 91 350 is a good base but should i modify the stocks head on it or opt for the 081 heads, modify those and put them on the motor. I hope i dont sound too stupid asking these questions. Im 18 and i understand how motors work i just dont have the unbelievable knowledge must of you guys have. This is all just one big learning experience for me. So dont think if you explain these things in detail i will be offended, i will accept it graciously. Sorry for going a little off topic just want to take the chance to say thanks to you guys and this website. It has helped me so much.

 

:hail:

 

The 083 casting heads (L98 cast iron, if that is what you get) will require less work machine work if staying with the 1.94/1.50 valve sizes. 081 heads have 1.84/1.5 valve sizes. 64 cc for the 083s versus 58cc in stock un-modified form. It's a personal decision on which head to use. Strip them down and take a look to see the differences for yourself. If one set is cracked/damaged...then that decides for you. Either one will get the power your after...but don't go overboard on spending money on either.

If you want to try the 305 head on a 350...do some searches for F-BIRD'88 and heads.

For modifying the 350 L98 cast iron heads (64cc stock without combustion chamber mods) read up on this series of posts...as well as F-BIRD'88's posts.

https://www.thirdgen.org/techbb2/sho...hreadid=183264

https://www.thirdgen.org/techbb2/sea...der=descending

 

The 081 heads are definatly perfered over a TBI head
for a budget performance buildup.
They are essentually L-98 heads with smaller chambers and smaller valves.

Be sure to install larger 1.94 x1.60valves and give 'em a generous porting and at least a 3 angle valve job.

You can easily resize the chambers to 64cc with generous "unshrouding" of the chamber. Lots of room for creativity.

You want a finshed actual compression ratio of 9.8/ 10:1
for 92/94 octane.

A performer RPM or a Vic Jr intake will work.
Use a 750cfm carb.

I like the RPM for a street car.

A cam with about 230 to 240 deg@.050 is needed.

Hyd roller if its in the budget.
A solid is a good option too if you don't mind periodic valve lash adjustment.
Something around 244 to 252 @..050 is right for a solid.

Plan on a 3000/3500stall converter and some rear gear
for best results.

 

Thanks for the input. I was wondering though if it would be smart to stay with fuel injection. I want to use a stealth ram with my tpi fuel rails, upgraded 24lb/hr injectors and a larger throttle body. Would that work?

 

If i went to my local machine shop roughly how much money could i expect to pay for larger valves, three angle valve job and porting and polishing the heads.

 

Ok so this is the set up im looking at right now. Please feel free to add you two cents and make any constructive criticism. I still have know idea what is the best cam to use. All i know is i still need street driveability and able to idle. (somewhat)

1. 350 v8 from 91z
2. Speed pro forged pistons 9.72:1
3. Stock Rods and Crank (new hardware)
4. l98 heads; ported, polished, 1.94/1.60 valves with three angle valve job
5. Stealth ram intake, 24lb/hr inj., 52mm tb, tpi fuel rails
6. Comp Cams hyd roller 230/244 .510/.540 (unsure what is best cam to use)
7. Either edelbrock tes headers or hooker 2055 headers
8. 3in exhaust, no cats with flowmaster mufflers

How much power do you think this set up will make and what else can i do to squeeze out as much power as possible.
Thanks

 

That will make good power, but with that cam you will need a 3.73 gear and a higher than stock (2800-3500) stall converter to make it pull strong off the line. I would run a Hot Cam just because it will have more low end torque for driveability, it is cheap and won't have to have near as much converter. You will need tuning for sure if you stay injected.
You might want to consider buying some new heads instead of spending a bunch on your L98 heads because you can get more money in lesser heads than you could buy good ones for. Look at some Pro Toplines, they are good heads and are very reasonably priced. If you pay someone to port your stock heads you will have at least $500 in them after they are finished(including valve job & resurfacing)
Good luck,
Charlie

 

Do your own porting on your heads. Then have the machine shop finish them.

If you can't or won't do that its not worth paying a shop to port stock heads.
Just buy aftermarket heads.
Other than that it all sounds good.

 

So your saying this cam profile will suit me better.
218/228 .525/.525 Its an lt4 hot cam

 

It just depends on what you want out of the car. It's all compromises, everything you do will be limited by how you want the car to drive at lower RPMs, how much you want to spend, how much power do you want, how high do you want to spin the motor, how much gas milage do you want and so on. I just think if you aren't planning on getting a torque convertor and gears with your combo the hotcam will work better. It will have more low RPM torque than the Comp 306 but will not make as much top end power. It is a good compromise camshaft and work good in street cars with stock or near stock convertors/gears.
Good luck,
Charlie