Klickmania

So it's time for new heads for this guy and I'm a little lost. I have a non-roller 5.0L block out of a '71 Fairlane/Torino that's been converted to a roller set up with the f cam. I'm on a pretty tight budget and I am looking at a set of rebuilt GT40's. Onto the questions:

Will the GT40's bolt right on without headers/spark plug issues? I know the later style GT40s have an extra tube on the back of them for emissions or something like that. Also, I believe I have the stock headers off of a '92 GT.

Will they require new pushrods? (Wouldn't a set of stock length roller pushrods (6.272") work just fine? I currently have a set of universal 6.385" Edelbrock pushrods with stock, as far as I know, rockers and springs. Here's a link to the pushrods I currently have. http://www.summitracing.com/parts/EDL-9655/ )

Will i need dual valve springs due to the lift of the cam too?

I really appreciate any and all input on this. I'm kind of on a tight deadline as well. I'm heading off to school in a few weeks and I need to get this sorted out before I leave. Thanks again!

- Spencer

Klickmania

Bump.

sn95_331_GT_ yellow

yank your engine and buy one of the cheap FRPP crate engines and drop that in if you want easy...

Klickmania

First off, I'd never buy a pre-assembled engine...Yes, even from Ford Racing. Also, if I had that kind of money laying around I'd be building a whole new roller motor and we wouldn't be having this discussion. But unfortunately I have a fairly limited budget and time constraints. So I though maybe...just maybe someone on here could answer a few questions for me.

I guess not.

enix187

why is everybody so easily offended lately, this is more tech forum questions man. I'll give you answers to the best of my knowledge.

the gt40 heads, bolt right up, as long as they aren't later style gt40s known as gt40p's you can use the stock headers, but the stock ones are absolute sh*t, get some ebay shorty's or bbk uncoated shorties, along the lines of the pushrods buy news ones, you need to measure for them with the heads installed (thats chevy tech so don't take it as canon). You have an f cam, from what i understand thats old tech (not a cam guru) so just go to lunati and get some stock style springs to make your life easier.

and yes, a lot of the guys on this forum that could be helpful much prefer to give guys asking simple questions hell but a few (reall a few) guys on here are extremely helpful

sn95_331_GT_ yellow

any late model head is going to have the Thermactor set up on it, be it a GT40, GT40P, E7TE, etc...

as for the pushrods, measure with the new heads. no it shouldnt make difference but **** happens.

having a roller cam in a non roller block means 1 of 2 things:
-either a small base circle cam with stock lifters (which you dont have)
or
-stock cam (f303 in your case) with retro-fit lifters.

either one will require different length pushrods. how long? i dont know.

springs will need to be upgraded. hell i got mine to float on my stock 95 cam, which is WAYYYYY less aggressive than a stock fox, let alone anything upgraded (letter cams are a SLIGHT step above stock). TFS makes a good set of upgrade springs for the stock heads around ~$150 IIRC...

stock "headers" are 1.5" primaries into a 2.25" collector. anything aftermarket will be at least 1.625" into 2.5", if not 1.75" into 2.5".

nightmare90gt

as for headers i would get long tubes cant tell you much about the engine still learning about the pushrod 302's

AdderMk2

If you can't back up your post with logic, reason, or experience.... dont post.


OP, SN95_331 is correct. The ONLY way to know what pushrods will be correct is, unfortunately, going to require you to measure them.

You need to bolt the heads on, use a low tension checking spring(or convert one of your lifters to solid), and use an adjustable pushrod length checker, to find the proper rocker to valve tip roll pattern.

As for headers, use an using an unequal length shorty will be fine.
Use Autolite 764 spark plugs, and spark plug wires with 90° boots, and you shouldnt have any issues.

The GT40's WILL have the thermactor hols on the back side of the heads. Which is less than a problem, not even an inconvenience. While the heads are off, grab some carb cleaner and a battery terminal bottle brush. spray inside the threads, and clean with the brush. Then use a 5/8-11x1" bolt with a washer or two, in each hole. I always suggest using some red or copper RTV on this bolt. but never loctite. The bolt wont come out, so loctite isnt necessary.

Klickmania

I definitely appreciate all the responses guys! Looks like I'm gonna have to wait to get heads now so I don't really have the time constraints I originally though. I'm more then likely going to get a set of gt40 heads here some time in the future, but we'll see.

Thanks a bunch guys! You answered a lot of my questions and I'll definitely be sure to come back if I have any other questions.

- Spencer

NT83stangGT

hey i also had to replace my heads on my 83, which is a non roller as well
i picked up some heads off a 90' 5.0 and ported them out myself, they bolt right in no problem no new push rods or nothing and i noticed a HUGE increase in power, over all it was cheep and easy, as long as u know what your doing
but i was in the same situation as you, i almosty bought the GT 40 heads but this just seemed easier since i knew they wouldnt give me any troubles